Despite suffering a heart attack which necessitated treatment in Paris, Stratos was again elected in absentia as MP for Aetolia-Acarnania in the February 1956 elections, now with the Greek Rally's successor, the National Radical Union. He then served as head of the Greek delegation to the 12th session of the United Nations General Assembly. Re-elected in 1958, he became Minister for Social Welfare throughout Konstantinos Karamanlis' third cabinet (17 May 1958 – 20 September 1961), and again after the 1961 elections from 4 November 1961 until his resignation on 20 December 1962.
