A system for closed transfer of fluids includes a vial adapter having a body with a first end and a second end, a vial connection extending from the second end of the body, with the vial connection configured to secure the body to a vial, a vial spike extending from the second end of the body, with the vial spike defining a passageway, and a collet connection extending from the first end of the body. The system further includes a syringe adapter including a housing having a first end and a second end, a membrane housing positioned within the housing, with the membrane housing moveable between a first position and a second position, a cannula positioned within the housing, and a syringe connection extending from the first end of the housing, with the syringe connection configured to be secured to a syringe barrel.