Musculature samples of oesophagus, heart, diaphragm, tongue, masseter and skeletal muscles from each of 52 horses and 130 donkeys were microscopically examined by both,compressorium and trypsin digestion techniques omnivorous for detection Of Sarcocystis infection. The infection rate reached 88.5% in horses and 91.5% in donkeys: The sarcocysts were detected in all examined samples with the highest rate in esophagus (100%). The morphology and size of 
the detected Sarcocysts, metrocytes and bradyzoites in both, horses and donkeys were found to be similar. The cyst wall was thick (>2 um)  and appeared striated. Experimentally infected dogs with horse or donkey meat excreted sporocysts measuring 12.2 - 14.6 X 9.0 - 10.7 um and 12.0 - 14.9 X 8.3 - 10.7 um . respectively. The prepatent period was 10 - 14 days. It was concluded that Sarcocystis infecting both, horses and donkeys in Egypt could belong to the same 
species (Sarcocystis bertram!)