A segmented core (1) for molding of an impeller (12), especially a pump impeller, includes at least three segments (2). All of the segments (2) have the same form and each segment (2) has connecting devices (3, 3′) for connecting the segment (2) with the adjacent segments (2). A method for molding an impeller (12) includes the steps of: providing a molding tool (14), providing a core (1) including at least three identical segments (2), which include the connection portions (3, 3′) for connecting the segment (2) with the adjacent segments (2); assembling of the core (1); placing the core (1) in the molding tool (14); molding the impeller (12), ejecting the core (1) and the impeller (12) out of the molding tool (14); and removing the core (1) from the impeller (12).