Micoscopic examination was done for total, and differential leukocytic count and parasitological examination for intestinal parasites and mange mite. Biochemical serum analysis for estimation of total protein, albumin, globulin, A/G rato, electrophoresis and vitamin E was also performed. Total leukocytic count showed no significant difference due to intestinal parasitic infestation, although eosinophilia was found in moderate and heavy intestinal parasitic infestation. Leukopenia, neutropenia and eosinophilia were found in mange mite infection. Hypoproteinemia and hypoalbuminemia with significant decrease in A/G ratio were predominant in heavy intestinal infestation and in mange. Mild and moderate intestinal infestation showed no significant difference in serum total protein, although there was a low A/G ratio in moderate infestation. There was non-significant difference in alpha-1 and alpha-2 globulins between diseased and apparently healthy horses, However, there was non-significant increase in beta-1 and beta-2 globulins and significant increase in gamma globulin in horses with heavy intestinal infestation and with mange mite infection. A significant difference was found in serum levels of vitamin E between diseased and healthy control groups, There was a positive correlation between the drop of serum levels of vitamin E and the degree of intestinal parasitic infestation. A correlation was also found between serum levels of vitamin E and serum levels of gamm globulins. It can be concluded that the infection with intestinal parasites and mange mite, specially when it is heavy and prolonged for long time, has a marked stress effect on body immune efficiency.