A wild, 3-wk-old saker falcon (Falco cherrug) nestling showing uncoordinated movements and a perosis type tarsometatarsus deformity was found abandoned; it was euthanized a week later on 29 May 1997 after an unsuccessful attempt to rehabilitate it. Gross pathological findings included congestion of parenchymal organs and a lateral bowing of the left tarsometatarsal bone. Histopathology revealed initial interstitial hepatitis, focal catarrhal pneumonia, and dyschondroplasia in the epiphysis of the left tarsometatarsus. Mycoplasmas were isolated from the lungs, trachea, bone marrow and brain. A polymerase chain reaction (PCR) assay was performed for the detection of the mycoplasmal 16S rRNA gene. The resulting 262 base pair PCR product was sequenced and compared to the available mycoplasmal sequences but no identical corresponding sequences were found. However, 98% similarity was found to the Mycoplasma buteonis 16S rRNA and the isolate also was positive by immunoblotting against reference sera to the same species.