A drainage catheter delivery system for positioning a drainage catheter or stent within a body cavity, such as a ureter. The delivery system includes a guide catheter, a push catheter, a drainage catheter (or stent) and a retention device. The guide catheter includes an outer diameter sized to slidably receive the push catheter and the drainage catheter. In this regard, the push catheter is placed over the guide catheter proximal the drainage catheter. The retention device selectively connects the push catheter to the drainage catheter. During use, the delivery system is pre-assembled as described above. The assembled delivery system is directed within a body cavity such that a distal end of the guide catheter is in close proximity to the desired drainage catheter position. The push catheter is axially slid along the guide catheter to move the drainage catheter away from a proximal end of the guide catheter. Conversely, the drainage catheter is retracted, or moved toward the proximal end of the guide catheter by retraction of the push catheter. Retraction of the push catheter retracts the drainage catheter via the retention device. Once properly positioned, the drainage catheter is released from the retention device by retracting the guide catheter from the drainage catheter.