The invention resides in the field of introducing fluid pumps into a lumen and relates to a system for introducing a pump into a lumen which comprises a first sheath and a pump to be introduced into the first sheath, or a system which has a pump with a distal pump unit and a shaft catheter which emerges proximally to the pump unit. According to the invention one or two sheaths are used, the distal pump unit being pulled firstly into the distal end of one sheath, in order to avoid damage to a shaft catheter. Subsequently, the sheath receiving the pump unit is transferred into a further sheath or a receiving lumen.
