Republican senators could add to their record-high majority. Republicans have a 32-16 edge; Republicans won two seats in the August primary runoff that previously had been held by Democrats.
Voters will choose senators in 12 districts. Seven senators are seeking re-election.
In the House, Republicans are hoping to at least reach their record high of 70 after the 2010 elections. One death and two unfilled vacancies put the tally at 67-31 at the end of this year's session.
House Speaker Pro Tempore Jeff Hickman, R-Fairview, said Monday he wouldn't be surprised if the House Republicans number 75 after Tuesday's voting.
Thirty-four House seats will be decided in Tuesday's election.
Twenty-two incumbents, 16 Republicans, and two Democrats, hope to return for another two-year term. After the primary and runoff elections, House Republicans hold a 47-20 majority.
In addition, voters will decide whether to retain 12 state appellate court judges. Four state Supreme Court justices, three judges on the Oklahoma Court of Criminal Appeals and five judges on the Oklahoma Court of Civil Appeals are on the ballot.
Voters will mark “yes” or “no” whether the judges should keep their offices another six years.
Voters also will decide the state of six state questions. Issues requiring a change in the state constitution must win voter approval.
This year voters are being asked whether to:
• Place a 3 percent annual cap on the amount county assessors can increase appraisals.
• Prohibit the use of affirmative action in state government.
• Remove the governor from the parole process.
• Authorize the Oklahoma Water Resources Board to issue bonds to finance a reserve fund for water and sewage treatment projects.
• Abolish the governing commission of the state Department of Human Services, which would clear the way for a new structure and the governor appointing the agency's director under a law passed and signed into law this year.
• Exempt all intangible personal property tax from ad valorem property taxation.
Many counties across the state have sheriff races on the ballot Tuesday, including Oklahoma, Cleveland, Canadian, Logan and Lincoln counties.
In Oklahoma County, Sheriff John Whetsel is being challenged by Darrell Sorrels, a retired sheriff's deputy.
Other countywide offices were decided earlier in the year. Court Clerk Carolynn Caudill went unchallenged in her re-election bid, while County Commissioner Brian Maughan defeated his opponent in the primary and Tim Rhodes became the new court clerk in an August runoff election.
In Payne County voters will consider allowing liquor by the drink sales on Sunday. Currently bars in the county, which is the home of Oklahoma State University, are not allowed to sell liquor on Sundays. The measure has been on the ballot twice, in 1986 and 1988 and was defeated both times.
Voters in Moore will consider a $25.1 million bond issue to fund parks projects, including a new community center, an amphitheater, jogging trails and an aquatic center. There is also a quarter cent sales tax on the ballot in Moore that would go to fund improvements and repairs at existing parks.
STAFF WRITER MEGAN ROLLAND