Many anatomical and histological text books denied the presence of muscularis mucosa in the urinary bladder while other recent studies described its structure in different patterns. Sections were taken from cystectomies, biopsies and autopsies and were stained by Hx & E, Masson trichrome and Desmin immuno-histochemistry. Muscularis mucosa was examined and correlated to different age ,sex and species. The incidence, pattern, distribution and localization were described and tabulated in different species.