The 2012 winners are listed below. Read more about the contest.
| Regular Division | |||
| Place | Student | School | Teacher |
| 1st | Elaine Reichert | Parkway Central High School | Ken Greathouse |
| 2nd | Joshua Zeid | Parkway Central High School | Ken Greathouse |
| 3rd | Jeffrey Cheng | Clayton High School | Mike Howe |
| 4th | Jonathon Brand | Parkway Central High School | Ken Greathouse |
| 5th | Aaron Argyres | Clayton High School | Mike Howe |
| HM | Shiori Tomatsu | Clayton High School | Mike Howe |
| HM | William Nickerson | John Burroughs School | Eric Knispel |
| HM | Noah Youkilis | Clayton High School | Mike Howe |
| HM | Alexander Wei | Parkway Central High School | Ken Greathouse |
| HM | Alex Yoffie | Parkway Central High School | Ken Greathouse |
| HM | Jason Roodman | John Burroughs School | Sandra Mueller |
| HM | Louis Wang | Parkway Central High School | Ken Greathouse |
| HM | Ari Ginsparg | Parkway Central High School | Ken Greathouse |
| HM | Joseph Mayer | Parkway Central High School | Ken Greathouse |
| HM | Sasha Ashall | John Burroughs School | Eric Knispel |
| Advanced Division Students who do well in the Advanced Division qualify for the National Chemistry Olympiad. Names of qualifiers for the National Chemistry Olympiad exam are initalics. No more than two students may qualify from a single school. HM = honorable mention |
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| Place | Student | School | Teacher |
| 1st | Runpeng Liu | Ladue High School | Carl Tenpas |
| 2nd | Apoorva Sharma | Clayton High School | Nathan Peck |
| 3rd | Ellie Gund | Clayton High School | Nathan Peck |
| 4th | Paul Lisker | Clayton High School | Nathan Peck |
| 5th | Noam Kantor | Clayton High School | Nathan Peck |
| HM | Cynthia Sung | Visitation Academy | Steven Bockhold |
| HM | Meizi Liu | Clayton High School | Nathan Peck |
| HM | Harrison Garrett | Clayton High School | Nathan Peck |
| HM | Gray Harlan | Clayton High School | Nathan Peck |
| HM | Dylan Schultz | Clayton High School | Nathan Peck |
| HM | Dan Zeng | Clayton High School | Nathan Peck |
| HM | David Behrend | Clayton High School | Nathan Peck |
| HM | Sharjeel Zahid | Parkway Central High School | Ken Greathouse |
| HM | Nick Goel | John Burroughs School | Sandra Mueller |
| HM | William Wysession | Clayton High School | Nathan Peck |