On November 3, 1992, Missouri voters approved by a margin of 75 percent an amendment to the state's constitution (Article III, Section 8) limiting the years a legislator may serve in the General Assembly. Prior to this provision, Missouri had no legislative term limits.
As originally adopted, the amendment limited the service of individuals elected to the General Assembly to a maximum of eight years in the Missouri House of Representatives and eight years in the Missouri Senate. The amendment also excluded from term-limit calculations any legislative service initiated from elections held prior to the original term limits effective date of December 3, 1992.
In 2002, voters amended the term limit provision (Article III, Section 8) to allow those filling seats vacated after a term's midpoint the opportunity to subsequently run for up to four complete two-year House terms and/or up to two complete four-year Senate terms. Prior to this provision, any partial service counted as a full term, effectively becoming the first of four possible two-year House terms and/or the first of two possible four-year Senate terms.
Lawmakers completing un-expired terms at the time of the partial service provision's 2002 passage must still count their partial service as full terms in term-limit calculations. Senator Victor Callahan was the first Senate member able to exclude partial service from his term limit calculation.
In the Senate, term limits render three current members ineligible to run for Senate re-election in 2006. Five current members will be ineligible to run for Senate re-election in 2008.
These numbers are subject to change as members may resign, retire or be defeated at their next election.
As of January 5, 2005, the average years of experience in the Senate decreased from 6.7 years to 1.85 years.
| District | Name | Elected | Party | Ineligible to Run In | Notes |
| 1st | Harry Kennedy | 2001 | D | 2008 | 1 |
| 2nd | Scott T. Rupp | April, 2006 | R | 2014 | 2 |
| 3rd | Kevin Engler | 2004 | R | 2012 | |
| 4th | Pat Dougherty | 2001 | D | 2006 | 3 |
| 5th | Maida Coleman | Feb., 2002 | D | 2008 | 4 |
| 6th | Carl Vogel | 2002 | R | 2010 | |
| 7th | John Loudon | 2000 | R | 2008 | |
| 8th | Matt Bartle | 2002 | R | 2010 | |
| 9th | Yvonne Wilson | 2004 | D | 2012 | |
| 10th | Charles Wheeler | 2002 | D | 2010 | |
| 11th | Victor Callahan | Nov., 2003 | D | 2012* | 5 |
| 12th | David Klindt | 2001 | R | 2006 | 3 |
| 13th | Tim Green | 2004 | D | 2012 | |
| 14th | Rita Days | 2002 | D | 2010 | |
| 15th | Michael Gibbons | 2000 | R | 2008 | |
| 16th | Frank Barnitz | April, 2005 | D | 2014 | |
| 17th | Luann Ridgeway | 2004 | R | 2012 | |
| 18th | John Cauthorn | 2001 | R | 2006 | 3 |
| 19th | Chuck Graham | 2004 | D | 2012 | |
| 20th | Dan Clemens | 2002 | R | 2010 | |
| 21st | Bill Stouffer | 2004 | R | 2012 | |
| 22nd | Bill Alter | April, 2005 | R | 2014 | |
| 23rd | Chuck Gross | 2000 | R | 2008 | |
| 24th | Joan Bray | 2002 | D | 2010 | |
| 25th | Rob Mayer | 2004 | R | 2012 | |
| 26th | John Griesheimer | 2002 | R | 2010 | |
| 27th | Jason Crowell | 2004 | R | 2012 | |
| 28th | Delbert Scott | 2002 | R | 2010 | |
| 29th | Jack Goodman | Nov., 2005 | R | 2012 | 6 |
| 30th | Norma Champion | 2002 | R | 2010 | |
| 31st | Chris Koster | 2004 | R | 2012 | |
| 32nd | Gary Nodler | 2002 | R | 2010 | |
| 33rd | Chuck Purgason | 2004 | R | 2012 | |
| 34th | Charlie Shields | 2002 | R | 2010 | |
Notes:
1) Senator Kennedy completed more than half of a partial term before winning re-election to a full term in 2004, when all 17 odd-numbered districts were up for election. (Even if his partial term service were less than half of a full four-year term, the partial term exclusion still would not apply as Sen. Kennedy was in office during the provision's passage.)
2) Senator Jon Dolan vacated the 2nd District Senate seat in November 2005 to take a position in the private sector. As less than half of the vacated term remained, the incoming Senator, Scott T. Rupp, can stand for re-election in November of 2006 and again in 2010.
3) Senators Cauthorn, Klindt and Dougherty were all elected to serve out partial terms. While their partial terms were less than half of full four-year terms, none could have their partial service discounted from their term limit calculations as they were in office at the time the partial term provision was adopted. All three Senators won re-election to full four-year Senate terms in November 2002, but are ineligible to run again for the Senate in 2006.
4) Senator Coleman completed more than half of a partial term before winning re-election to a full term in 2004, when all 17 odd-numbered districts were up for election. (Even if her partial term service were less than half of a full four-year term, the partial term exclusion still would not apply as Sen. Coleman was in office during the provision's passage.)
5) Senator Callahan was the first member following the 2002 passage of the partial term provision elected to a seat vacated after the term's midpoint. Having won re-election to a full term in 2004, Sen. Callahan could run for re-election once more in 2008.
6) Senator Goodman was first elected to the 29th District Senate seat in a November 2005 special election held to fill the seat vacated by the July 2005 passing of Senator Larry Gene Taylor. As Sen. Goodman will be serving more than half of the late Sen. Taylor's un-expired four-year term, Sen. Goodman will only be eligible to run once (in 2008) for re-election to the Senate.
Missouri Constitution Article III - Legislative Department
Section 8 - Term limitations for members of General Assembly.
Term limits language as originally adopted November 3, 1992
