Injections are frequently administered by occupational health nurses in worksite health promotion programs. The purpose of this study was to examine the effect of varying injection speed on the perception of pain. Fifty workers were given intramuscular (i.m.) hepatitis B vaccine at injection speeds of 10 and 30 seconds per cubic centimeter (s/cc). The perception of pain was measured on a visual analogue scale and reported post-injection at three different time intervals. The results showed that no difference in pain was perceived by participants between the two injection speeds. Results also revealed that women consistently had higher mean pain scores than men and significantly more pain at the 0 hour measurement of the 10 s/cc injection. While the results of this study indicate no need to administer an i.m. injection slower than 10 s/cc, occupational health nurses will need to consider gender differences in pain perception when administering injections.