Somerset County Cricket Club competed in four domestic competitions during the 2009 English cricket season: the first division of the County Championship, the Friends Provident Trophy, the first division of the NatWest Pro40 League and the Twenty20 Cup. Through their performance in the Twenty20 Cup, the team qualified for the Champions League Twenty20. They enjoyed a successful season, but fell short of winning any competitions, prompting Director of Cricket Brian Rose to say "We've had enough of being cricket's nearly men."
Consistent performances in the County Championship helped Somerset remain challengers for the competition until the last few weeks of the season, but the batting-friendly pitch at their home ground, the County Ground, Taunton, meant that the county finished with too many draws to claim their first Championship title. Consistency was also key for Somerset's success in one-day cricket, where they remained unbeaten in the group stage of the Friends Provident Trophy, but were eliminated in the first knock-out round, and finished runners-up by one point in the NatWest Pro40. In the Twenty20 Cup, Somerset finished as losing finalists. This meant that they qualified for the Champions League Twenty20, where they progressed into the second group stage of the competition. They failed to win any matches in that phase of the competition, resulting in their elimination.