A catheter pump is disclosed herein. The catheter pump can include a catheter assembly that comprises a drive shaft and an impeller coupled to a distal end of the drive shaft. A driven assembly can be coupled to a proximal end of the drive shaft within a driven assembly housing. The catheter pump can also include a drive system that comprises a motor and a drive magnet coupled to an output shaft of the motor. The drive system can include a drive assembly housing having at least one magnet therein. Further, a securement device can be configured to prevent disengagement of the driven assembly housing from the drive assembly housing during operation of the pump.