Fecal samples from 1488 pigs were collected from six pig farms in Jiangsu provinceand Shanghai,eastern China,stained by the modified acid-fast staining technique(MAFS) andobserved by light and phase contrast microscopy to identify Cryptosporidium oocysts. A total of178(12％) positive animals were detected. Three randomly selected MAFS-positive samples fromeach farm were further analyzed by RT-PCR using primers designed to amplify DNA fragmentsfrom the small subunit ribosomal RNA(SSU rRNA) gene. PCR products from two positive sampleswere sequenced. Phylogenetic analysis and a distances matrix generated from these sequencesshowed that the isolates belonged to the species C. parvum,and were most similar to the C. parvum"mouse" genotype. The identification of this C. parvum genotype in pigs has not been reportedpreviously. These findings are discussed in the context of the epidemiology of Cryptosporidium onpig farms.