This study aimed to isolate the most common pathogens causing diarrhea in calf in addition to studying the hematological, biochemical, and fecal changes associated with the disease. The study was conducted on 44 calves, 31 diarrhea-diseased cases and 13 animals were apparently healthy and were served as control. Hematological, biochemical, and fecal changes were investigated through examining whole blood, serum and fecal samples collected from both healthy and diseased groups. The results implicated that Eimeria and Toxocara were the most common parasitic pathogens isolated from both healthy and diseased animals. Hematological parameters showed a significant increase in red cell parameters including red cell count, hemoglobin, and packed cell volume as well as total leukocytic counts in the diseased group compared to control. Significant increases were observed in the serum enzymatic activities of ALT, AST, ALP GGT, amylase and lipase.  Serum concentrations of glucose, urea, BUN, creatinine were significantly increased, whereas serum levels of total protein, albumin, triglyceride, Na, K and Cl showed a significant decrease.  No significant changes were observed in blood pH and bicarbonate levels in the diarrheic animals when compared to control group. We can conclude that Eimeria and Toxocara appeared to be the main parasitic causes of diarrhea in calf. The disease is associated with significant hematological, and biochemical alterations which upon understanding can provide a good knowledge of the pathogenesis and thus controlling the condition in calf.