Abstract: Catheter for delivery of a medical device such as a stent or filter includes an inner tubular member and an outer tubular member movable relative to the inner tubular member. The outer tubular member is disposed at the distal end of the inner tubular member. The inner tubular member includes a fluid lumen defined therein, the fluid lumen having a fluid flow port directed to the exterior surface of the inner tubular member. A pressure chamber is defined by the inner tubular member, the outer tubular member, a proximal seal and a distal seal, and is in fluid communication with the fluid flow port, wherein fluid introduced through the fluid flow port and into the pressure chamber applies a force on the proximal seal to move the outer tubular member in a proximal direction allowing the medical device constrained by the outer tubular member to be released.