Sacrum is an important bone for identification of sex in human skeletal system. Being a component of axial skeleton it contributes to formation of pelvic girdle. This cross sectional and descriptive study was done among 150 (59 male and 91 female) fully ossified dry human sacrum in Mymensingh Medical College, Mymensingh, Bangladesh from January 2017 to December 2017. Sample collection was done by non-random purposive sampling technique from Anatomy department of Mymensingh Medical College and Community Based Medical College, Bangladesh, Mymensingh. The parameters included the straight length of sacrum and width of sacrum which was measured by digital vernier slide caliper and was expressed in millimeter (mm) and sacral index was calculated from these measurements. In present study the mean straight length of sacrum in male and in female was 104.27±5.76mm and 92.82±7.59mm respectively. The mean width of sacrum in male and in female was 99.51±5.80mm and 102.98±6.69mm respectively. Mean sacral index were 95.42±3.14 and 111.27±7.66 in male and female respectively. Comparison of straight length and width of sacrum and sacral index were done between male and female by unpaired student 't' test which was statistically significant.