A Mediterranean monk seal was shown by immunohistochemical and polymerase chain reaction techniques to be dually infected with a Leishmania sp. and parapoxvirus. The pathological findings included a deep ulcer on the side of the head, ulcers on the gingival and inner aspect of the lower lip, enlarged lymph nodes and tonsils, and respiratory lesions (pulmonary consolidation, oedema, haemorrhages and emphysema; tracheal and bronchial congestion, exudates and haemorrhage). Amastigotes were demonstrated in macrophages in the lymph nodes and spleen, and intracytoplasmic inclusion bodies were observed in the tracheal and oral mucosa.