The Z-track intramuscular injection technique was compared with the standard injection technique for incidence and severity of discomfort and lesions at the injection site. Fifty subjects received injections of meperidine hydrochloride alone or in combination with promethazine hydrochloride every 3 to 4 hours for a total of two to eight injections. Subjects served as their own controls by receiving both techniques. They were evaluated for the presence and severity of discomfort on a 4-point Likert scale. Injection site lesions were determined by visualization and palpation. The Z-track technique significantly decreased incidence of selected descriptors of discomfort and lesions at selected time intervals, severity of discomfort at selected time intervals, and severity of lesions at all time intervals postinjection.