Toxic megacolon is one of the fatal complications of inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn’s disease (CD). It is not very common for UC to present for
the first time during pregnancy, especially with complications like toxic megacolon. Here, we have described a case of megacolon in a primigravida in late second trimester most probably due to IBD. The baby was delivered via cesarean section, and the mother was managed conservatively. Postnatal periods for both mother and baby were uneventful.