A total of 100 apparently normal quarter cow's milk samples were collected under aseptic condition and examined cytobacteriologically and chemically for detection of subclinical mastitis. The koestler No. could detect subclinical mastitis in 42 out of 84 milk samples (50%) which showed >3. The agreement percentage between modified white side test (MWT) and bacteriological examination were 81.82% for 2+ve and 3+ve respectively, while the false negative results was 39.24%. On the other hand, the agreement percent between somatic cell count/ml and bacteriological examination was 80.95% in which 21 samples showed a count more than 500.000 cells/ml. Out of them 17 samples were positive for bacteria. The isolated bacteria were found to be Str. agalactiae (10.42%), Str. dysgalactiae (4.17%), E. coli (14.58%); Staph. aureus (22.91%); Staph. epidermidis (25%) and Cory. pyogenes (4.17%) for the single infection, while Str. agalactiae with Staph. aureus and Str. agalactiae with E. coli were found to be 12.5% and 6.25. Respectively for the double infection. In conclusion, it is evident that early detection of infected gland is the most important factor in the control of mastitis by applying screening tests supported by confirmatory bacterialogical examination.