Abstract Avian mycobacteriosis has been documented commonly in poultry, companion birds, and birds in zoological collections or wildlife parks. However, reports in free-ranging raptors are relatively rare. We describe 6 cases of mycobacteriosis in free-living raptors. Four red-tailed hawks (Buteo jamaicensis), 1 red-shouldered hawk (Buteo lineatus), and 1 great horned owl (Bubo virginianus) were presented for examination after being found on the ground unable to fly. Common clinical findings in these birds included coelomic distention or palpable coelomic mass, nonregenerative anemia, and leukocytosis characterized by heterophilia, monocytosis, and lymphopenia. Results of radiography, ultrasonography, coelomoscopy, and biopsy, in combination with acid-fast staining of specimens obtained by biopsy or fine-needle aspiration, provided evidence of a presumptive diagnosis of mycobacteriosis. All birds were euthanatized (n = 5) or died (n = 1). At necropsy, diffuse granulomas with intralesional acid-fast bacill...