This experiment was conducted on Holstein-Friesian cross-bred cows to investigate the major haemato-biochemical parameters and their correlation with cylicity and non-cyclicity. Accordingly, 24 apparently healthy cows of about 3 – 7 years of age were divided into cyclic and non-cyclic groups based on the presence or absence of corpus luteum on the ovaries. Significantly higher (p<0.05) levels of Hb, PCV, TLC and neutrophil were observed in the cyclic cows. Non-significant alteration was found for TEC, lymphocyte, monocyte and basophil between the two groups, whereas eosinophil count was significantly higher in non-cyclic cows. There was also significant increase in the levels of total protein, urea and cholesterol in non-cyclic group as compared to cyclic group; while non-significantly higher glucose level was noticed in cyclic cows. Our study suggests that urea, cholesterol and total protein level may be potential risk factors effecting cyclicity in Holstein-Friesian cross-bred cows. 1299317318.php