Den første single fra albummet "Left Behind" blev nomineret til den 44. [[Grammy Awards|Grammyuddeling]] i kategorien [[Grammy Award for Best Metal Performance]] i 2002.<ref name="BM.Grammy2002">{{cite news |title = Slipknot's Paul Gray: "I Know System Of A Down Will Win Grammy" |publisher = Blabbermouth.net |date = 2002-02-27 |url = http://www.roadrunnerrecords.com/blabbermouth.net/news.aspx?mode=Article&newsitemID=1780 |access-date = 2007-12-16}}</ref> Den anden single "My Plague" blev efterfølgende i 2003 nomineret i samme kategori til den 45. Grammyuddeling.<ref name="BM.Grammy2003">{{cite news |title = Grammy Awards Nominees Announced! |publisher = Blabbermouth.net |date = 2003-01-07 |url = http://www.roadrunnerrecords.com/blabbermouth.net/news.aspx?mode=Article&newsitemID=8702 |access-date = 2007-12-16}}</ref> "Left Behind" nåede indenfor top 30 på USAs og Storbritanniens singlesalgslister.<ref name="billboard2">{{cite web|url = http://www.billboard.com/bbcom/retrieve_chart_history.do?JSESSIONID=JT55GLbQG2qLJ51p2542kGkXrT1YNrqc1CTVhycLHG2zlHpg1V9f!1701541563&model.vnuArtistId=33923&model.vnuAlbumId=774595|title = Billboard.com Artist Chart History - Slipknot|publisher = Nielsen Business Media Incorporated|access-date = 2008-01-26|archive-url = https://web.archive.org/web/20070929174958/http://www.billboard.com/bbcom/retrieve_chart_history.do?JSESSIONID=JT55GLbQG2qLJ51p2542kGkXrT1YNrqc1CTVhycLHG2zlHpg1V9f!1701541563&model.vnuArtistId=33923&model.vnuAlbumId=774595|archive-date = 29. september 2007|url-status=live}}</ref><ref name="UKCharts">{{cite web|url=http://www.everyhit.com/|title=UK Top 40 Chart Archive, British Singles & Album Charts|publisher=everyhit.com| access-date=2008-02-07}}</ref> Yderligere nåede "My Plague" plads 43 på Storbritanniens hitliste.<ref name="UKCharts"/> I 2001 placerede ''NME'' albummet ''Iowa'' på sjettepladsen i deres kategori "50 af årets største albums."<ref name="NMEb"/> 
Albummet fik yderligere en topposition på Storbritanniens albumhitliste,<ref name="UKCharts"/> og en anden plads i Australien.<ref name="Australian Charts"/> Både på ''[[Billboard 200]]'' og i Finland nåede det tredjepladsen.<ref name="Finland"/> Den 5. september 2001 i Canada gav [[Canadian Recording Industry Association]] albummet [[certificering af musiksalg|platin]],<ref name="CRIA Database">{{cite web| url=http://www.cria.ca/cert_db_search.php| title=Search for: Iowa| publisher=Canadian Recording Industry Association| access-date=2008-02-07| archive-date=11. januar 2016| archive-url=https://web.archive.org/web/20160111074458/http://www.cria.ca/cert_db_search.php| url-status=dead}}</ref> og den 10. oktober 2001 blev albummet yderligere tildelt platin i USA.<ref name="RIAA Database">{{cite web|url=http://www.riaa.com/goldandplatinumdata.php?table=SEARCH| title=Search for: Iowa| publisher=Recording Industry Association of America| access-date=2008-02-07}}</ref> [[British Phonographic Industry]] certificerede senere albummet guld i Storbritannien.<ref>{{cite web |title = Iowa Certified Awards |publisher = British Phonographic Industry |date = 2001-08-24 |url = http://www.bpi.co.uk/platinum/platinumright.asp?rq=search_plat&r_id=29583 |access-date = 2008-02-10 |archive-date =  5. juni 2008 |archive-url = https://web.archive.org/web/20080605043822/http://www.bpi.co.uk/platinum/platinumright.asp?rq=search_plat&r_id=29583 |url-status = dead }}</ref>
Musik