In April, Mahmood was selected to represent the England Lions against the West Indies. Despite being overlooked by England for the first Test of the summer, in May Mahmood secured his career-best bowling figures and his maiden 10-wicket haul. In a Lancashire victory over Worcestershire by six wickets, Mahmood took 6/75 and finished with match figures of 10/140. Mahmood was one of several Lancashire bowlers unable to play in August 2009. He, Glen Chapple, Steven Cheetham, and Tom Smith were injured and Andrew Flintoff and James Anderson were on England duty. As a stop-gap measure, Tom Lungley was loaned by Lancashire from Derbyshire County Cricket Club. After he finished the season with 41 first-class wickets at an average of 34.00, and 24 list A wickets at an average of 23.33, Mahmood was recalled to the England One Day International squad for their tour of South Africa in the winter of 2009.