Dissertation (MMED General Surgery)Background: Sigmoid volvulusis twisting of the sigmoid colon along its mesocolic axis either clockwise or anticlockwise leading to closed loop luminal obstruction and sigmoid vascular obstruction. Surgical anatomy of sigmoid colon has been linked to development of sigmoid volvulus but few studies have been done, nonefrom Tanzania. Objective:The study aimed at determining surgical anatomy of sigmoid colon insigmoid volvulus and non-sigmoid volvulus patients who underwent laparotomy at Iringa and Dodoma Regional Hospitals in Tanzania. Methodology: Study area: Iringa and Dodoma Regional Hospitals. Subjects: 62in-patients who underwentlaparotomy with 31 sigmoid volvulus and 31 non-sigmoid volvulus indications from May 2017 to April 2018. Study design: Hospital-based case-control study. Sampling method& data collection: Convenient sampling method and intraoperatively measuring of sigmoid colon anatomical parameters.Analysis: Cleaned and codded data were analysed by software SPSS 20, descriptive and inferential (t-test and regression) statistics were done with significance level of P<0.05. Results: The sigmoid colon, sigmoid mesocolic height and sigmoid mesocolic width were longer in sigmoid volvulus patients than in non-sigmoid volvulus patients. The sigmoid mesocolic basal width was not significantly different in sigmoid and non-sigmoid volvulus patients. Conclusion and Recommendation:The sigmoid volvulus is associated with elongated sigmoid colon with long and wider mesocolon. Variations in sigmoid mesocolic widths in volvulized sigmoid colon to be further researched in future studies with larger samples, matched ages and sex.