Subcutaneous administration of the anticoagulant heparin sodium is a frequently performed nursing intervention. Subcutaneous heparin injection often causes problems such as bruise, pain, induration, and hematoma at the injection site. Bruising that result from heparin injections may lead to anxiety, disruption of body image, the rejection of the treatment in patients, and the reduction of the reliance of patient to nurse. The purpose of this study was to determine and compare the effects of four different injection technique pain and on bruising associated with subcutaneous heparin. The research involved ninety-five patients. Each subject received four injections by the same investigator using four different techniques. Site bruising was measured at forty-eight and seventy-two after each injection. The bruising size was measured using milimetric transparent palyethylene wrap and the verbal pain scale. There was significant difference in the incidence or size of bruises and pain perception the subject among techniques. Results of the study show that use of air lock technique without aspiration and two-minute cold application to the area of injection with methods reduce bruise and pain.