To facilitate the spread of safe techniques in laparoscopic surgery, in medical faculties in Japan we created two forms for laparoscopic nephrectomy and prostatectomy that consisted of a global rating scale (GS) and our task checklist (TS) using objective structured assessment of technical skill (OSATS). We examined the correlation between the global rating scale total score (GS) and the task checklist total score (TS), and the difference in GS and TS between the instructor' s assessment and the practitioner' s self-assessment, and compared the differences in the scores at each operative step. GS was found to be closely correlated with TS (P<0.05). Where there were differences between GS and TS, the instructor-assessed GS was higher than the self-assessed score in nephrectomy (P<0.05). However, there was no significant difference between instructor- and self-assessed scores in prostatectomy. In nephrectomy, the instructor-assessed score was higher than the self-assessed score (P<0.05) for "creation of an operating field" and "dissection of surrounding tissue of the kidney". Assessment forms created using OSATS would be useful for quantifying the surgical skill in laparoscopic surgery. In the future, we plan to use the assessment forms to assist in surgical education and assessment.