Abstract: Serum levels of glucose, total proteins, calcium and phosphorus were determined by light absorption spectrophotometry in cycling, non-cycling, repeat breeder and endometritic buffaloes (n = 16 in each group). The cycling buffaloes had significantly higher levels of glucose than the other three groups (P<0.05). The total protein concentration was significantly higher in cycling as compared to endometritic and non-cycling buffaloes (P<0.05). The significantly higher calcium concentration was determined in cycling buffaloes as compared to rest of three groups. The level of inorganic phosphorus was significantly higher in repeat breeder and cycling group of buffaloes (P<0.05). It was inferred from the present study that lower concentrations of blood glucose, total protein and calcium and higher concentrations of inorganic phosphorus might account for non-cycling, repeat breeding and endometritis in buffaloes.