Mastitis is an important disease which causes economic losses in the water buffalo breeding. According to severity, duration and primary, mastitis is generally classified as clinical and subclinical. Because of contamination from other animals in the herd, subclinical mastitis is a important dairy herd problem. However, clinical mastitis is a clinical case created by deformation of udder gland and decreasing milk yield. Staphylococcus aureus, Escherichia coli, Streptococcus agalactia and Streptococcus dysgalactia are in clinical mastitis, but Escherichia coli, Staphylococcus aureus, Pseudomonas, Streptococcus agalactia and Streptococcus dysgalactia are the most common isolated microorganisms in subclinical mastitis. Due to mastitis caused by these microorganisms in Water Buffalo, abnormality in the structure of milk are observed, and it causes economic losses to farmers from reduced production. Therefore, the detection of effective factors on mastitis and taking of the necessary precautions are very important. In this review, mastitis case in water Buffalo and its effects were discussed.