Between mid-July and early August, an unusual mass mortality of cetaceans was detected on the Turkish Western Black Sea coast. 114 cetaceans (53 harbour porpoises, 9 common dolphins, 7 bottlenose dolphins, 45 unidentified) were reported dead and nine common dolphins stranded alive, 6 of which were returned to the sea. Only two freshly dead common dolphins were subjected to a complete necropsy, sampling and tissue analysis. Tissue samples from brain, lung, spleen, liver, kidney, muscle and testis were fixed in formalin and embedded in paraffin. Histological analysis was conducted and immunohistochemical technique to detect morbillivirus antigen was applied. RNA and cDNA samples were examined for dolphin morbillivirus (DMV) detect by reversetranscription–PCR (RT-PCR) and conventional PCR. Main histopathological lesions were multifocal non-purulent meningitis, severe diffuse alveolar oedema in lung samples, multifocal periportal macrovacuolar hepatic steatosis, interstitial and tubular degeneration with protein casts and calcifications in renal medulla. No evidence for DMV infection was analytically found in both dolphins, and the cause of this unusual mortality is still uncertain.