This study was carried out on 28 diseased buffalo calves suffered from anorexia, elevation in body temperature, depression with varying degrees of dehydration and diarrhoea with offensive odour and bloody mucoid discharge. Other ten clinically healthy buffalo calves served as control group were also included. These calves were belonging to the farm of faculty of Veterinary Medicine, Suez Canal University. Enteropathogenic E. coli (12 isolates), Salmonella sp. (5 isolates) and Pseudomonas sp. (8 isolates) were recovered and identified from diseased rectal samples and incriminated as the causative agent of diarrhoeic neonatal calves. Bacteriological examination of different locations of calve's yard soil and water troughs was carried. This examination revealed the presence of E coli, Proteus sp., Citrobacter sp., Klebsiella sp., Pseudomonas sp., Shigella sp., and Alcaligens feacalis in different percentages. The hematological study was conducted on blood samples of apparently healthy and diseased calves showed significant increase in both total erythrocytic and leucocytic count, packed cell volume and haemoglobin concentration in diarrhoeic calves versus to the control ones. Blood serum biochemical analysis revealed significant decrease in the level of total protein, glucose, sodium and chloride, while blood serum potassium level was significantly increased in diarrhoeic calves than in control ones. Excellent improvement in clinical symptoms, blood picture and blood serum constituents were observed following treatment with ampicillin 20% in combination with fluid therapy and application of good sanitary measures.