The present study aims to diagnose the predominant types of Clostridium perfringens from the cases of diarrhoea in cattle from Tamil Nadu. A total of 16 rectal swabs were aseptically collected from same number of cattle and were processed for the isolation and identification of C. perfringens. The molecular typing of the bacteria was carried out by the polymerase chain reaction assay, which revealed the identification of 14(87.5%) C. perfringens isolates from diarrhoeic cattle. The ultrastructure studies of the bacterial isolates in SEM were observed to be in clusters of thick rods with variable in length and mostly occurred in pairs. Out of six toxin genes namely alpha toxin (cpa), beta toxin (cpb), epsilon toxin (etx), iota toxin (iA), enterotoxin (cpe) and beta2 toxin (cpb2) used for typing the isolates, only cpa of 324bp fragment were detected from all the 14 isolates. The PCR result suggested that isolates from the diarrhoeic cattle belonged to the C. perfringens genotype A, which is also the most frequently isolated genotype of C. perfringens in cattle. PCR has established a sensitive and reliable investigative tool for the rapid detection of C. perfringens.