Abstract: An inserter assembly comprising a first unit including a skin contacting face which surrounds an opening and a second unit housed within the first unit. The second unit comprises an infusion set base disposed within the opening and having a bottom face which is substantially level with the skin contacting face and covered at least partially with adhesive and further comprising a spring biased insertion assembly. The second unit further comprising a cannula sub assembly carried by an insertion sharp of the insertion assembly. The spring biased insertion assembly and a cannula of the cannula sub assembly are driven into skin and the cannula sub assembly is coupled into the infusion set base by an insertion spring which is released from an energy storing state after the skin has been tugged upward beyond a certain distance by the adhesive as the inserter assembly is withdrawn from the body.