The aim of this study was to investigate which parameters would be used as prognosis and mortality indicators in newborn calves with diarrhea. Fifty-one newborn calves with diarrhea were used in the study. Calves with diarrhea were divided into two groups as non-surviving (n=16) and surviving (n=35). After routine clinical examinations of all calves, blood was drawn for hematological, blood gases and biochemical analyzes. Diarrhea, dehydration, decrease in suckling reflex, prolonged capillary refill time, hypothermia and increased respiratory rate were determined in all calves. The calves that were non-surviving and surviving had severe metabolic acidosis and an increase in potassium levels. Compared with the surviving calves, it was observed that the non-surviving calves with diarrhea had significantly (P<0.05) higher blood lactate levels and significantly (P<0.05) lower blood glucose, mean corpuscular hemoglobin concentration (MCHC), total protein (TP) and gamma glutamyl transferase (GGT) levels. When the lactate cut-off value was 4.5 mmol/L between non-surviving and surviving calves, the sensitivity and specificity were found to be 81.3% and 71.4%, respectively. As a result, it was evaluated that blood lactate and glucose levels can be used as prognosis and mortality indicators in calves with neonatal diarrhea, and low levels of TP and GGT activities may be a predisposing factor for diseases due to passive transfer failure.