In a statement released Tuesday, Ryan says the "most important factor in making this decision was determining where I could make the biggest difference."
Ryan adds that serving as chair of the Budget Committee is best for him and "allows me to have greater impact in averting this debt-fueled crisis if I were to run for the United States Senate."
Had Ryan run, this would have been a referendum on his budget and Medicare package, which is still likely to front and center in the presidential contest with Obama visiting a swing state like Wisconsin around the clock.
Read Ryan's full statement below:
"I am grateful for the tremendous outpouring of encouragement that I have received from my friends and supporters since Senator Kohl announced he would not seek re-election to the U.S. Senate. For my family and me, the most important factor in making this decision was determining where I could make the biggest difference. Our nation is quickly approaching a debt crisis that will do serious damage to Wisconsinites and all Americans if it is not properly addressed. I believe continuing to serve as Chairman of the House Budget Committee allows me to have a greater impact in averting this debt-fueled economic crisis than if I were to run for the United States Senate.
House Republicans have taken bold steps forward in tackling our fiscal and economic challenges - we have led, where others have not. I want to keep building on this progress and therefore, I will seek to continue serving my employers of Wisconsin's First District as their Representative in the House."