Our aim was to develop a method for species diagnosis and to obtain data on the prevalence of Sarcocystis infections in cattle and water buffalo in the Son La Province of Northern Vietnam. Meat samples of naturally infected animals were examined by light and electron microscopy as well as by molecular methods. A PCR of part of the 18S rDNA gene followed by RFLP analysis was modified to detect infections with different Sarcocystis spp. in cattle and water buffaloes slaughtered in the Son La Province. It showed to be an economical method to detect multiple infections with Sarcocystis spp. Sequence analysis of the PCR amplicons was performed with selected samples and the results were compared with published sequences. With these methods the following Sarcocystis spp. were identified in cattle: Sarcocystis hirsuta, Sarcocystis cruzi and Sarcocystis hominis. Water buffaloes were infected with Sarcocystis fusiformis, S. cruzi, S. hominis and S. hirsuta. The results indicate that Sarcocystis spp. infecting cattle are also able to infect water buffaloes. So the validity of certain Sarcocystis spp. of water buffalo is discussed. Bovine lifestock in Northern Vietnam were commonly infected with Sarcocystis spp.