The purpose of this study was to determine if applying pressure to the site for 10 sec prior to an intramuscular injection would reduce injection pain, an approach suggested by anecdotal observation and the gate control theory. The subjects were 93 patients who had dorsogluteal intramuscular injections of immune globulin at a county health department. Forty-eight received the pressure treatment and 45 received a standard injection in which no pressure was applied. Mean pain intensity on a 100-mm visual analogue scale, adjusted for differences in injection volume, was 13.6 mm for the experimental group and 21.5 mm for the control group (P = 0.03). The findings suggest that simple manual pressure applied to the site is a useful technique to decrease injection pain.