The main ecosystems within the mountain range are rainforest giving way to dense bamboo forests and then moorland. The steep western edges of the hillside are sparsely inhabited by wildlife compared to the forested gentle slopes to the east, which are home to a wide variety of wildlife. There are multitudes of elephant, buffalo, giant forest hog as well as the endangered Black Rhino. A variety of cats including leopards and the rare African Golden Cat. Other threatened species including the Jackson mongoose, the black and white Colobus monkey and Sykes monkey are plentiful, as are waterbuck, reedbuck, duikers, serval cats and bushbuck.
The Aberdares contain a rich diversity of vegetation. There are 778 vegetation and plant species, subspecies and varieties found in the Aberdare National Park, due to the park's altitude and rainfall. Hardwood trees include camphor, Cedar, Podo and Hagenia.