The prevalence of Sarcocystis species in muscle samples from gazelles kept as breeding groups at the King Khalid Wildlife Research Centre, Saudi Arabia, was deterined by fibreoptic examination, pepsin digestion and histological techniques. No macroscopic sarcocysts were detected by fibreoptic examination, and the overall prevalence of Sarcocystis was 66.7 per cent by pepsin digestion, and 39.9 per cent by histological examination. By digestion, the tongue contained the highest density of bradyzoites in Gazella dorcas, and Gazella gazella erdangeri, the oesophagus in Gazella subgutturosa marica and skeletal muscle in Gazel/a gazella and Gazelha thomsoni. Skeletal muscle was least affected in G dorcas, the oesophagus in G gazella, and the diaphragm in G gerdangeri, G s marica and G thomsoni. By histology, the heart contained most microcysts, except in G g erlangeri, in which the tongue was most affected. No single tissue type was therefore suitable for the diagnosis of sarcocystosis in this multispecies collection, although digestion was more sensitive in detecting infection than histology. The level of Sarcocystis infection was significantly higher in free-ranging gazelles kept in a main enclosure than in gazellas kept in breeding pens, and higher in adult gazelles than in juveniles.