A system for connecting a hemostasis valve to a splittable sheath includes an interface formed between a ledge on the proximal end of a cannula portion of the hemostasis valve and an engagement structure aligned with the handles of the splittable sheath. Pulling the handles to split the sheath likewise disengages the ledge from the engagement structure. A snap ring on the cannula portion engages a snap ring in the lumen of a sheath hub formed on the proximal end of the splittable sheath. An O-ring between the cannula portion and the sheath hub provides a fluid-tight seal.