The authors describe the first parasitological survey of protozoal infections on tissue slide sections of field cases processed at the histopathology laboratory of the College of Veterinary Medicine (CVM) at the University of the Philippines Los Baños (UPLB). Over 80% of the field cases were from Region 4 (CALABARZON) and the rest were equally distributed from other areas of the Philippines, namely: Region 2 (Cagayan Valley), Metropolitan Manila (National Capital Region), Region III (Central Luzon) and Region VI (Western Visayas). Histopathological analyses of tissue sections from 51 archived cases (1972-2010) of parasitic aetiology were performed. Microscopic examination of a total of 286 histopathological slides revealed the presence of several protozoa, including sarcosporidiosis, hepatic coccidiosis, intestinal coccidiosis, balantidiosis and leucocyto-zoonosis. In addition, the finding of Balantidium and Sarcocystis may have zoonotic implications and can therefore be used as markers of public health importance.