| 2024 | Antariksha Sharma, Maharishi SAE, Fairfield (B) Ishita Mukadam, Maharishi SAE, Fairfield (B) Benjamin Lothamer, Mid-Prairie HSAP, Kalona (P) |
| 2023 | Sidney Gruntmeir, Central Lee HS, Donnellson (B) Everlee Harvey, Central Lee HS, Donnellson (B) Jacob Hohl, Central Lee HS, Donnellson (B) |
| 2022 | Grace Helle, Beckman HS, Dyersville (B) Kelly Takorbisong, Keokuk HS, Keokuk (P) Jayden Shin, West HS, Iowa City (B) |
| 2021 | Jasmyn Hoeger, Beckman Cath HS, Dyersville (B) Meena Ramadugu, Kennedy HS, Cedar Rapids (B) |
| 2020 | Dasia Taylor, West HS, Iowa City (B) Meena Ramadugu, John F Kennedy HS, Cedar Rapids (P) Shristi Sharma, Maharishi Sch, Fairfield (P) |
| 2019 | Kayla Livesay, Van Buren HS, Keosauqua (B) Amara Orth, Lewis Central HS, Council Bluffs (B) |
| 2018 | Brooklyn Pardall, Central Lee HS, Donnellson (B) Aaron Wills, Central Lee HS, Donnellson (P) |
| 2017 | Manasa Pagadala, Rivermont Collegiate, Bettendorf (B) Mason Burlage, Beckman HS, Dyersville (B) Aaron Wills, Central Lee HS, Donnellson (P) |
| 2016 | Sweta Sudhir, Kennedy HS, Cedar Rapids (B) Doga Ozesmi, Fairfield HS, Fairfield (P) |
| 2015 | Sweta Sudhir, Kennedy HS, Cedar Rapids (B) Liana Suleiman & Clara Reynen, Burlington HS, Burlington (P) |
| 2014 | Kaylie Wilson, Central Lee HS, Donnellson (B) Bimba Shrestha, Maharishi SAE, Fairfield (P) |
| 2013 | Lydia Heald, Van Buren Comm HS, Keosauqua (B) Brice Plein & Nick Whitcomb, Burlington Comm HS, Burlington (P) |
| 2012 | Micaela Bryant, Central Lee HS, Donnellson (B) Surekha Mullangi, Burlington Comm HS, Burlington (P) |
| 2011 | Cayla Pieper, Holy Trinity Jr-Sr HS, Fort Madison (B) Atreya Dey, Maharishi SAE, Fairfield (P) |
| 2010 | Nikhil Dhuna, Burlington Comm HS, Burlington (P) Lynnely Parker & Bailie Bryant, Central Lee HS, Donnellson (P) Pavane Gorrepati, Rivermont Collegiate, Bettendorf (P) |
| 2009 | Pandy Wadsworth & Yogita Singh, Maharishi SAE, Fairfield (B) Shelby Sieren, Keota HS, Keota (P) |
| 2008 | Xiaomeng Zeng, West HS, Iowa City (B) Shelby Sieren, Keota HS, Keota (P) |
| 2007 | Megan Bartholomew, Central Lee HS, Donnellson (B) Hannah Dotseth, Burlington Comm HS, Burlington (P) |
| 2006 | Emma Pardini, Solon HS, Solon (P) Subha Subramanian, Home Schooled, Iowa City (B) |
| 2005 | Amy Marquardt, Mediapolis HS, Mediapolis (P) Cory Millmier, Central Lee HS, Donnellson (B) |
| 2004 | Michael Fosdick, Mediapolis HS, Mediapolis (B) Rachael Collier, Mediapolis HS, Mediapolis (B) |
| 2003 | Sara Weirather, Central Lee HS, Donnellson (B) Arie Schiller, Central Lee HS, Donnellson (B) Tim Kirchner, West HS, Iowa City (P) Amy Marquardt, Mediapolis, Mediapolis (P) |
| 2002 | Sara Weirather, Central Lee HS, Donnellson (B) Rachael Collier, Mediapolis HS, Mediapolis (B) Joanne Wenke, Central Lee HS, Donnellson (P) Joe Hove, Solon, Solon (P) |
| 2001 | Ashley Noreuil, Washington HS, Cedar Rapids (B) Amber Hohl, Central Lee, Donnellson (B) JD Greiner, Keota Jr/Sr HS, Keota (P) Blake Forsythe, Harmony HS, Farmington(P) |
| 2000 | Michelle Punj, Maharishi SAE, Fairfield (P) Imelda Turner, Iowa City West HS (P) Arie Schiller, Central Lee HS, Donnellson (B) Amber Hohl, Central Lee HS, Donnellson (B) |
| 1999 | Carol Fassbinder, Valley CEW, Elgin (B) Jason Weirather, Central Lee, Donnellson (P) |
| 1998 | Blake Forsythe, Farmington (P) Katherine Beger, Central Lee, Donnellson (B) |
| 1997 | Sara Rees, Marshalltown HS (B) Alicia Schiller, Central Lee, Donnellson (B) |
| 1996 | Carol Fassbinder, Valley CEW, Elgin (B) Kelly Weirather, Central Lee, Donnellson (B) |
| 1995 | Christine Micheel, Marshalltown (P) Alicia Schiller, Donnellson (B) |
| 1994 | Christopher Burke, Marshalltown (P) Candice Kelley, Fairfield (B) |
| 1993 | Sarah Renze, Marshalltown (B) Christine Micheel, Marshalltown (P) |
| 1992 | Marci Thomas, Marshalltown (P) Heather Levi, Fairfield (B) |
| 1991 | Alan Adams, C.R. Regis (B) Eric Berggren, Marshalltown (B) |
| 1990 | Alan Adams, C.R. Regis (B) Eric Berggren, Marshalltown (B) |
| 1989 | Alan Adams, C.R. Regis (B) Abram Siemsen, Fairfield (P) |
| 1988 | Michelle Wells, Marshalltown (B) Gareth Wallace, Fairfield (B) |
| 1987 | Michelle Wells, Marshalltown (B) Bill Denniger, Marshalltown (B) |
| 1986 | Robert Wallace, Fairfield (B) Daniel Smith, Farragut (P) |
| 1985 | Goeffrey Francis, Marshalltown (P) Bryan Young, Cedar Falls (P) |
| 1984 | Darin O'Brien, Stuart-Menlo (P) Jane Kothenbeutel, Marshalltown (B) |
| 1983 | Darin O'Brien, Stuart-Menlo (P) John Stellwagen, Iowa City (B) |
| 1982 | Kyle Holland, Stuart-Menlo (P) Douglas Grier, Marshalltown (B) |
| 1981 | Kevin Rhodes, Marshalltown (B) Kent Rhodes, Marshalltown (B) |
| 1980 | Kevin Rhodes, Marshalltown (B) Jennifer Haerer, Muscatine (B) |
| 1979 | Shelley Jones, Muscatine (B) Craig Brophy, C.R. Jefferson (P) |
| 1978 | Kevin Rhodes, Marshalltown (B) James Mitchell, Alburnett (P) |
| 1977 | Bryan Lessley, C. R. Jefferson (P) Deanna Sieren, Tri-County (B) |
| 1976 | Roger Lessley, C. R. Jefferson (P) Karen Morris, Alburnett (B) |
| 1975 | Tim Martin C.R. Regis (B) Steve Tjaden, Midland Comm. (P) |
| 1974 | Susan Yohn, Muscatine (B) Tom Nelson, Iowa City (P) |
| 1973 | Gordon Waite, Maquoketa (P) Evelyn Elkins, Maquoketa (B) |
| 1972 | Gordon Waite, Maquoketa (P) Mike Yoder, Wellman Mid-Prairie (B) |
| 1971 | Robert Skelley, Maquoketa (P) James Herwig, Muscatine (B) |
| 1970 | Robert Skelley, Maquoketa (P) Deborah Miller, Maquoketa (B) |
| 1969 | Alan Heyvaert, C.R. Regis (B) Douglas Beadle, Marion (P) |
| 1968 | Leslie Parker, C.R. Regis (B) Allan Holtz, Maquoketa (P) |
| 1967 | Christine Havlich, C.R. Regis (B) Ronald Rogers, Iowa City Regina (P) |
| 1966 | Terrance Goder, C.R. Regis (B) Philip Dorothy, Dubuque (P) |
| 1965 | Sue Bohlin, Iowa City (B) Larry Orcutt, Newhall (P) |
| 1964 | Dennis Crouse, Marion (B) David Walker, Iowa City (P) |
| 1963 | Dennis Crouse, Marion (B) Paul Roling, Dubuque Wahlert (P) |
| 1962 | Dennis Crouse, Marion (B) Gary Wulfsberg, Washington (P) |
(B) = Biological Exhibit, (P) = Physical Exhibit
1962–1966: Thomas Cech, Iowa City, exhibitor at EISEF, Junior & Senior Divisions
1989: Thomas Cech, Univ. of Colorado at Boulder, Nobel Prize in Chemistry