Abstract: A retention-type catheter adapted to be inserted, through the urethra, into the urinary bladder of a medical patient; the catheter including--in unitary relation--a primary tube for drainage of the bladder, a secondary tube for irrigation of the bladder, and an initially contracted but expansible retainer formed in the primary tube adjacent the tip thereof, the secondary tube being longitudinally movable relative to the primary tube and arranged to further serve as an exteriorly manually actuated, pull-push element operative to cause expansion and contraction of such retainer, respectively.