Introduction: Changing work patterns have led to reduction in training hours with potential to affect surgical skills training. Multimedia can be used to supplement cognitive surgical skills training outside the operating room. A systematic review of 21 studies on the role of multimedia in surgical training and assessment demonstrated that multimedia effectively facilitates acquisition of surgical skills and was associated with significant improvement in technical skills and cognitive skills. The aim of this project was to design and develop a multimedia educational tool in anterior resection surgery and evaluate the effectiveness of this tool in teaching and assessment of cognitive surgical skills. Methods: An online multimedia application was developed by filming multiple procedures; editing films into key procedural steps using cognitive task analysis; and integration onto a navigational interface platforms. All steps were supplemented with animation, text and voiceover. A randomised control trial was conducted to evaluate the effectiveness of online multimedia in comparison to conventional teaching in cognitive surgical skills acquisition. All trainees were assessed before and after the study period. Results: Of 59 trainees recruited, 52 completed pre-test assessments. Data from 43 trainees was available for final analysis. Baseline pre-assessment scores were similar in both groups. Senior trainees achieved significantly higher pre-test mean scores compared to junior trainees (p<0.01). Post-test scores improved significantly in both groups and the mean change in scores in the multimedia group was higher (6.60, SD 5.10) compared to the control group (4.89, SD 3.66) was not statistically significant (p=0.21). In the multimedia group 67% strongly agreed the tool was a useful adjunctive educational resource. 67% and 88% of trainees felt their cognitive surgical skills improved. Conclusions: Multimedia is an effective self-directed learning resource for cognitive skill acquisition in colorectal surgery and is well accepted as a training tool outside the operating room.