A 40 years old male Nile crocodile (Crocodylus niloticus) was diagnosed with pulmonary mycobacteriosis caused by a member of Mycobacterium chelonae/abscessus group. Post-mortem examination showed a severe systemic visceral granulomatous involvement, with lesions in lungs, heart, liver, spleen and kidneys. Histopathological examination of lung, spleen, heart and liver revealed multifocal to coalescing granulomas showing eterophils in central zone and outer rim of epithelioid histiocytes, multinucleated giant cells and lymphocytes. The Ziehl–Neelsen histological staining revealed rare vacuoles containing numerous alcohol-acid resistant bacteria. Mycobacterial infection was confirmed by culture and PCR targeting rRNA 16S gene. Sequence analysis of the DNA amplicon revealed a 100% homology with the M. chelonae/ abscessus group. Even if the classification of the memebrr of this group is still on updating, to the best of our knowledge, this is the first report of M. chelonae/abscessus member infection in a Nile crocodile species.