An ecological study was conducted in Bwindi Impenetrable National Park, Uganda to determine bryophyte species richness, their distribution along the altitudinal range, along streamsides and trails within the forests. Lower altitude mature mixed forest, medium altitude tropical evergreen and high altitude montane bamboo forest types were studied. Transects of 1000 m were laid and a 1 × 1 m quadrant was placed along each transect at an interval of 50 m. Abundance was measured using visual estimates of percentage cover of the bryophytes. Statistical analyses were performed using multivariate statistical package. Of the 131 bryophyte species collected, nine were new records to Uganda, five to East Africa and one (Eurrhynchium meridionale) to tropical Africa. Bryophyte richness was negatively correlated with altitude except for the thalloid hepatics, which increased with altitude. Bryophytes occurred mostly along the streamsides than along trails. Human disturbance appeared to affect bryophyte diversity. The tropical evergreen forest was the most diverse in terms of bryophytes followed by the mature mixed and bamboo forests. In spite of the low diversity, bamboo forest is important for hosting exclusively 17.6% of the collected bryophytes in this study one of which is a new record for Africa.