COLUMBUS, Ohio (AP) - U.S. Sen. George Voinovich of Ohio will not seek re-election in 2010.

Voinovich said in a statement Monday that the challenges facing the state and country will require him to devote all of his energy to serving out his current term and that campaigning and fundraising would take time away from his work as a senator.

Voinovich also said he wants to spend more time with his wife, children and grandchildren.

The decision sets in motion a jockeying among big names in both parties to replace Ohio's senior senator. It also brings to four the number of GOP Senate seats that won't have an incumbent in 2010.

Former U.S. Rep. Rob Portman of Cincinnati is figured to be a strong contender among Republicans to run for the Ohio Senate seat. Lt. Gov. Lee Fisher and U.S. Reps. Tim Ryan and Zack Space are potential Democratic candidates.

Written statement from Ohio Senator George Voinovich on his decision not to seek reelection:

After prayerful consideration and much thought, my wife Janet and I have decided that I will not seek a third term in the United States Senate.

As I spent time with my family during the holidays and celebrated Janet's birthday, I reflected on God's blessings on our family: my wife, our three children, our seven grandchildren and our health.

I also spent time thinking about the health of our country. In my lifetime of public service, I have never seen the country in such perilous circumstances. Not since the Great Depression and the Second World War have we been confronted with such challenges, as a nation and as a world.

Those of us that have been given the honor to serve in these times must step up to the plate and put this country on a course that will see it through these harrowing times and make it strong and viable for the 21st century.

These next two years in office, for me, will be the most important years that I have served in my entire political career.

I must devote my full time, energy and focus to the job I was elected to do, the job in front of me, which seeking a third term - with the money-raising and campaigning that it would require - would not allow me to do.

In addition, Janet and I have concluded that once my second term is complete, we should devote ourselves to our children and grandchildren. We have been blessed with good health, but we're no spring chickens. In 2010, I will be 74 years old and will have served 44 years in public office, having been elected to more public offices than any other person in Ohio history.

I am grateful for the opportunity that I have had to serve my statehouse district, my county, city, state and nation and feel good about the fact that with the help of some extraordinary people, many of whom are no longer with us, I have made a difference and will, with God's help and a great team in my Senate office, continue to make a difference during these next two critical years. We intend not to wind down-but to wind up, just like I did in the Mayor's office as well as the Governor's office.

We have a great deal to do in this Congress, and I will continue to focus on the areas that matter most: providing the nation a responsible stimulus package; jump-starting our credit markets; re-establishing confidence in the housing market and stemming the tide on mortgage foreclosures; harmonizing our nation's economic, energy and environmental policies; ensuring safe and stable highways; and continuing to improve the personnel and management of the federal government.

After the next two years, it will be time to give someone else the opportunity to serve our great state in the Senate, someone who can devote full time to organizing their campaign and raising the money necessary to win.

This has not been an easy decision for us. I still have the fire in my belly to do the work of our nation, but after serving the next two years, it will be time to step back and spend the rest of our time with our children and grandchildren, siblings and extended family and friends.

We both are confident that God has a plan for us to use the time, energy and talents that He has given us to make a difference in another way.