To study the thickness of interventricular septum (both muscular and membranous parts) of adult Bangladeshi people, fifty postmortem hearts were collected, fixed in 10% formol saline and examined. The thickness of both muscular and membranous parts of the septum was measured. Among fifty hearts, thirty-six were collected from male and fourteen from female cadavers. All hearts were collected from medicolegal cases. The findings were compared between male and female cadavers of our country as well as with the findings of the western countries. The findings suggest that in female, the thickness of both muscular and membranous parts of the septum was less than that of male though there was no significant difference statistically (P>0.05). The findings were compared with the findings of other workers and not so much variation was found. There was no available data regarding the thickness of the membranous part of the septum to compare.