Abstract: An adapter assembly is provided for fluid communication and mechanical connection between a catheter and a syringe. The adapter assembly includes a generally tubular nose having opposed proximal and distal ends. A wall is disposed at the distal end and includes an aperture dimensioned for receiving the catheter therethrough. A compressible plug is received in the open proximal end of the nose and seats against the wall. The plug includes an axial passage for receiving the catheter. Outer portions of the plug are tapered near the proximal end. The assembly further includes a hub having opposed proximal and distal ends. The proximal end of the hub includes luer projections for threaded engagement with a luer collar of a syringe. The distal end of the hub is threadedly engageable in the opened proximal end of the nose. Internal portions of the hub adjacent the distal ends are tapered and dimensioned to gradually compress the plug into fluid-tight engagement against the catheter without generating occlusion.