PURPOSE: This study was performed to evaluate the effectiveness of a pain assessment education program developed for nurses. METHODS: Research design of this study was nonequivalent control group quasi-experimental study. Subjects for this study were 56 nurses for control group, and 53 nurses for experimental group. The experimental group participated in pain assessment education program. Data were collected before and 6 months after the program and analyzed using the SPSS 12.0 program. RESULTS: The results of this study were as follows: In pretest, there were no significant differences in general characteristics, knowledge of pain, attitude toward pain and pain assessment behaviors. In post test, the experimental group had significantly higher scores of pain knowledge scores and pain assessment behaviors than control group. However, attitude toward pain remained unchanged. CONCLUSION: According to the results, pain assessment education program was effective in improving pain knowledge and pain assessment behavior.