when does george die grey's anatomy

George O'Malley dies in Grey's Anatomy in the first episode of season 6, titled "Good Mourning." He dies as a result of complications from injuries after being struck by a bus while saving a woman's life. His brain swells fatally during surgery, and despite the efforts of the doctors, he passes away. This episode marked the first absence of the character following T.R. Knight's departure from the show. George's death was a significant and emotional moment in the series, especially impacting characters like Izzie Stevens and Callie Torres who were close to him.