PURPOSE: The purpose of this study was to investigate the effect on pain of distraction with an operating doll in preschool children(3-6 years old) during an IV catheter insertion. METHOD: The research design was a nonequivalent control group posttest design, and the participants were 22 children in the experimental group, and 23 children in the control group. The children were hospitalized for enteritis and pharyngitis in a university hospital. The subjective pain was measured using FACES Pain Rating Scale by self report, and the pain behavior responses were scored using Procedure Behavior Check List by observing a film of the entire procedure, and changes in pulse and oxygen saturation as the physiological pain responses were measured by pulse oximeter. Data were analyzed with the SPSS Win 10.0 program. RESULT: The degree of subjective pain, pain behavior responses, and changes in pulse during IV catheter insertion were significantly lower in the experimental group. But there was no significant difference in O2 saturation between the two groups. CONCLUSION: Distraction using an operating doll was effective in decreasing pain during inserting the IV catheter in preschool children.