Анотация: The objective of the present work was to investigate the clinical, haematological and blood chemical changes associated with bovine viral diarrhoea (BVD) in local Iraqi calves. Out of 84 calves with clinical evidence of disease, 66 (55.44 percentage) were Elisa seropositive for BVD. Diseased calves with BVD showed anorexia (89.39 percentage), profuse watery diarrhoea mixed with mucus/or blood (78.78 percentage), dehydration (78.78 percentage), erosive lesions in the oral cavity (65.15 percentage), salivation (60.6 percentage), erosive lesions on the muzzle (48.48 percentage), petechial and ecchymotic haemorrhages of the visible mucosa (40.9 percentage), weakness (37.87 percentage) and lacrimation (31.81 percentage). Statistically significant increase has been detected in body temperature, respiratory and heart rates in diseased calves in comparison with controls (P<0.05). The haematological results of control and diseased calves showed no significant difference in erythrocyte count and haemoglobin, however packed cell volume values were significantly higher in diseased calves than in controls. Leukopaenia, lymphopaenia and thrombocytopaenia were encountered in diseased calves. The platelet volume, platelet distribution width, clotting time, prothrombin time and activated partial thromboplastin time values were significantly higher (P<0.05) in diseased calves. Blood biochemical changes revealed statistically significant (P<0.05) increased fibrinogen and haptoglobin concentrations in BVD calves