Abstract: Milk samples from 206 apparently healthy buffaloes of marginal farmers maintained under the prevailing field conditions were screened for Subclinical Mastitis (SCM) to determine its prevalence and etiology by White Side Test (WST), California Mastitis Test (CMT), Somatic Cell Count (SCC) and Bacteriological examination. 26.20% of animals were positive for SCM in SCC and bacteriological examination. Prevalence in graded Murrah buffaloes were found to be higher compared to graded Surti and Non-descript breeds. The prevalence of SCM was highest in above 6th stage of lactation. Single quarter infection (51.85%) was more common compared to multiple quarter infection. Hind (83.34%) and left side (57.41%) quarters were more prone to SCM. The indirect tests such as WST and CMT were found to be closely agreement with SCC and bacteriological examination. Due to their efficacious, easy to perform and interpret, these tests can effectively be employed to detect SCM under field conditions. Somatic cell count of = 3,00,000/ mL of milk was regarded as the upper limit for normal buffaloes. The SCC of = 3,00,000/mL of milk with positive bacterial growth were used to diagnose SCM in the present study. Staphylococcus sp. 25(46.30%) was the most common pathogens isolated from SCM followed by Streptococcus sp. 11(20.37%) and E. coli 06 (11.11%) of the 54 bacterial isolates. Monobacterial and mixed bacterial infections were observed in 47 (87.04%) and 7 (12.96%) cases respectively.