Detailed pathological and virological examinations were carried out on 25 cetaceans found stranded between 1990 and 1993 on the coasts of six Italian regions (Latium, Tuscany, Apulia, Abruzzo, Veneto and Sicily). There were 16 striped dolphins (Stenella coeruleoalba), three bottlenosed dolphins (Tursiops truncatus), three Risso's dolphins (Grampus griseus), one rough-toothed dolphin (Steno bredanensis), one fin whale pup (Balaenoptera physalus), and one minke whale (Balaenoptera acutorostrata). Apart from parasitic diseases (44 per cent), the most frequently detected lesions were pneumonia (68 per cent), enteritis (44 per cent), non-purulent hepatitis (40 per cent), interstitial nephritis (32 per cent) and encephalitis (32 per cent). Morbilivirus infection was diagnosed by immunocytochemistry in four striped dolphins, two stranded on the coasts of Latium in 1991 and two on the coasts of Tuscany in 1993. Despite the presence of lesions consistent with morbilliviral pneumonia in two other striped dolphins stranded on the coast of Apulia in 1991, no morbillivirus antigen was demonstrated in the tissues of these animals. Anticanine distemper virus antibodies were detected in the serum of the adult minke whale found stranded on the coast of Tuscany in 1993. However, no viruses were isolated from the tissues of any of the 25 cetaceans.