An adapter assembly (120) for connecting a catheter assembly (50,52) to a tunneler (110) having a generally tubular body (122) having a first end (124), a second end (126) and a longitudinal axis (128) extending therethrough between the first end and the second end. The first end (124) of the adapter is constructed to engage the proximal end (114) of a trocar (110). The second end (126) of the adapter is constructed to releasably engage at least one catheter lumen (50,52). A slider (140) is disposed about the adapter (120) and is longitudinally slidable along the adapter. When the slider (140) is slid towards the second end (126) of the adapter, the slider engages a plurality of legs (134a-134d) on the adapter and biases the plurality of legs toward each other and the longitudinal axis of the adapter. A method of subcutaneously tunneling a catheter using the adapter assembly is also described that comprises inserting a catheter into a patient, connecting the proximal end of a trocar to the adapter assembly, releasably restraining at least one lumen of the catheter in the adapter, and tunneling the assembly.