Per Curiam.
On June 12, 1974, respondent met for about 15 minutes with Don Connelly, a field representative of the Social Security Administration (SSA), and orally inquired of him whether she was eligible for “mother’s insurance benefits” under § 202 (g) of the Social Security Act (Act), 64 Stat. 485, as amended, 42 U. S. C. § 402 (g). Connelly erroneously told her that she was not, and she left the SSA office without having filed a written application. By the Act’s terms, such benefits are available only to one who, among other qualifications, “has filed application.” 42 U. S. C. §402 (g)(1)(D). By a regulation promulgated pursuant to the Act, only written applications satisfy the “filed application” requirement. 20 CFR §404.601 (1974). The SSA’s Claims Manual, an internal Administration handbook, instructs field representatives to advise applicants of the advantages of filing written applications and to recommend to applicants who are uncertain about their eligibility that they file written applications. Connelly, however, did not recommend to respondent that she file a written application; nor did he advise her of the advantages of doing so. The question is whether Connelly’s erroneous statement and neglect of the Claims Manual estop petitioner, the Secretary of Health and Human Services, from denying retroactive benefits to respondent for a period in which she was eligible for benefits but had not filed a written application.
Respondent eventually filed a written application after learning in May 1975 that in fact she was eligible. She then began receiving benefits. Pursuant to § 202 (j) (1) of the Act, she also received retroactive benefits for the preceding 12 months, which was the maximum retroactive benefit allowed by the Act. Respondent contended, however, that she should receive retroactive benefits for the 12 months preceding her June 1974 interview with Connelly. An Administrative Law Judge rejected this claim, concluding that Connelly’s erroneous statement and neglect of the Claims Manual did not estop petitioner from determining respondent’s eligibility for benefits only as of the date of respondent’s written application. The Social Security Appeals Council affirmed.
Respondent then brought this lawsuit in the District Court for the District of Vermont, which held that the written-application requirement was “unreasonably restrictive” as applied to the facts of this case. A divided panel of the Court of Appeals for the Second Circuit affirmed. 619 F. 2d 942 (1980). It agreed with petitioner as an initial matter that the regulation requiring a written application is valid and that the Claims Manual has no legally binding effect. But it considered the written-application requirement a mere “procedural requirement” of lesser import than the fact that respondent in June 1974 had been “substantively eligible” for the benefits. Id., at 948. In such circumstances, the majority held, “misinformation provided by a Government official combined with a showing of misconduct (even if it does not rise to the level of a violation of a legally binding rule) should be sufficient to require estoppel.” Ibid. In summarizing its holding, the majority stated that the Government may be estopped “where (a) a procedural not a substantive requirement is involved and (b) an internal procedural manual or guide or some other source of objective standards of conduct exists and supports an inference of misconduct by a Government employee.” Id., at 949.
Judge Friendly dissented. He argued that the majority’s conclusion is irreconcilable with decisions of this Court, e. g., Federal Crop Insurance Corp. v. Merrill, 332 U. S. 380 (1947); Montana v. Kennedy, 366 U. S. 308 (1961); INS v. Hibi, 414 U. S. 5 (1973) (per curiam), and with decisions of other Courts of Appeals, Leimbach v. Califano, 596 F. 2d 300 (CA8 1979); Cheers v. Secretary of HEW, 610 F. 2d 463 (CA7 1979).
We agree with the dissent. This Court has never decided what type of conduct by a Government employee will estop the Government from insisting upon compliance with valid regulations governing the distribution of welfare benefits. In two cases involving denial of citizenship, the Court has declined to decide whether even "affirmative misconduct” would estop the Government from denying citizenship, for in neither case was “affirmative misconduct” involved. INS v. Hibi, supra, at 8-9; Montana v. Kennedy, supra, at 314-315. The Court has recognized, however, “the duty of all courts to observe the conditions defined by Congress for charging the public treasury.” Federal Crop Insurance Corp. v. Merrill, supra, at 385. Lower federal courts have recognized that duty also, and consistently have relied on Merrill in refusing to estop the Government where an eligible applicant has lost Social Security benefits because of possibly erroneous replies to oral inquiries. See Leimbach v. Califano, supra, at 304-305; Cheers v. Secretary of HEW, supra, at 468-469; Goldberg v. Weinberger, 546 F. 2d 477, 481 (CA2 1976), cert. denied. 431 U. S. 937 (1977); Simon v. Califano, 593 F. 2d 121, 123 (CA9 1979); Parker v. Finch, 327 F. Supp. 193, 195 (ND Ga. 1971); Flamm v. Ribicoff, 203 F. Supp. 507, 510 (SDNY 1961). This is another in that line of cases, for we are convinced that Connelly’s conduct' — which the majority conceded to be less than “affirmative misconduct,” 619 F. 2d, at 948 — does not justify the abnegation of that duty.
Connelly erred in telling respondent that she was ineligible for the benefit she sought. It may be that Connelly erred because he was unfamiliar with a recent amendment which afforded benefits to respondent. Id., at 947. Or it may be that respondent gave Connelly too little information for him to know that he was in error. Id., at 955 (Friendly, J., dissenting). But at worst, Connelly’s conduct did not cause respondent to take action, cf. Federal Crop Insurance Corp. v. Merrill, supra, or fail to take action, cf. Montana v. Kennedy, supra, that respondent could not correct at any time.
Similarly, there is no doubt that Connelly failed to follow the Claims Manual in neglecting to recommend that respondent file a written application and in neglecting to advise her of the advantages of a written application. But the Claims Manual is not a regulation. It has no legal force, and it does not bind the SSA. Rather, it is a 13-volume handbook for internal use by thousands of SSA employees, including the hundreds of employees who receive untold numbers of oral inquiries like respondent’s each year. If Connelly’s minor breach of such a manual suffices to estop petitioner, then the Government is put “at risk that every alleged failure by an agent to follow instructions to the last detail in one of a thousand cases will deprive it of the benefit of the written application requirement which experience has taught to be essential to the honest and effective administration of the Social Security Laws.” 619 F. 2d, at 956 (Friendly, J., dissenting). See United States v. Caceres, 440 U. S. 741, 755-756 (1979).
Finally, the majority’s distinction between respondent’s “substantival eligibTility]” and her failure to satisfy a “procedural requirement” does not justify estopping petitioner in this case. Congress expressly provided in the Act that only one who “has filed application” for benefits may receive them, and it delegated to petitioner the task of providing by regulation the requisite manner of application. A court is no more authorized to overlook the valid regulation requiring that applications be in writing than it is to overlook any other valid requirement for the receipt of benefits.
In sum, Connelly’s errors “faipj far short” of conduct which would raise a serious question whether petitioner is estopped from insisting upon compliance with the valid regulation. Montana v. Kennedy, supra, at 314. Accordingly, we grant the motion of respondent for leave to proceed in forma pauperis and the petition for certiorari and reverse the judgment of the Court of Appeals.
It is so ordered.
This regulation has been recodified and now appears at 20 CFR §§404.602-404.614 (1980).
This section provides, in pertinent part:
“An individual who would have been entitled to a benefit under subsec-tio[n] . . . (g) ... of this section for any month after August 1950 had he filed application therefor prior to the end of such month shall be entitled to such benefit for such month if he files application therefor prior to the end of the twelfth month immediately succeeding such month. . . .” 42 U. S. C. §402 (i)(D-
Judicial review of final decisions by the Secretary is authorized by 42 U. S. C. §405 (g).
Justice Marshall cites several cases in which federal courts have applied estoppel against the Government. Post, at 791. In some of the eases, the Government had entered into written agreements which supported the claim of estoppel. E. g., United States v. Lazy FC Ranch, 481 F. 2d 985, 990 (CA9 1973); Walsonavich v. United States, 335 F. 2d 96, 100-101 (CA3 1964). In others, estoppel did not threaten the public fisc as estoppel does here. E. g.. Semaan v. Mumford, 118 U. S. App. D. C. 282, 284, and n. 6, 335 F. 2d 704, 706, and n. 6 (1964). In another, a bank claiming estoppel had erred in certain applications because it had to file before the Government would provide it with necessary information. United States v. Fox Lake State Bank, 366 F. 2d 962 (CA7 1966). We need not consider the correctness of these cases. We do think that they are easily distinguishable from the type of situation presented in this case and the line of cases we rely upon above.
The contention was made in Caceres that a violation of an internal IRS regulation concerning electronic eavesdropping should result in exclusion from trial of the evidence obtained by such eavesdropping. In rejecting this contention, we noted that such a per se rule “would take away from the Executive Department the primary responsibility for fashioning the appropriate remedy for the violation of its regulations. But since the content, and indeed the existence, of the regulations would remain within the Executive's sole authority, the result might well be fewer and less protective regulations. In the long run, it is far better to have rules like those contained in the IRS Manual, and to tolerate occasional erroneous administration of the kind displayed by this record, than either to have no rules except those mandated by statute, or to have them framed in a mere precatory form.” 440 U. S., at 755-756.