A total of 150 draught stallions 4-10 years old were used in this study, included 125 horses were naturally suffered from gastrointestinal and lung worms infection and 25 clinically normal draught horses served as control group. Coprological examinations revealed that draught horses were infected with many specieses belonged to nematodes and cestodes. The mean EPG were 2020 in McMaster method. Results indicated that diseased draught horses exhibited emaciation, rough coat, pale mucous membrane, black spots on the gum & lip, loss of appetite, diarrhea and/or constipation, worms with feces, mucous with feces, colic, anal pruritis, moist ralse, coughing and strong heart beat. Statistically, significant increase (P<0.01) were encountered between respiratory and heart rates of diseased horses in comparison with control, while there were no changes in body temperature among the two groups. Significant decrease (P<0.01) were encountered in the RBCS, Hb and PCV values of diseased horses, and significant increase (P<0.01) were also encountered in the sedimentation rates of RBCS, while there were significant increase (P<0.01) in WBCS and eosinophils. Results of biochemical tests indicated decrease in total protein and albumin values, the decrease was statistically significant (P<0.01). Levels of BUN and AST were increased significantly (P<0.01), while there were no significant changes observed in ALT levels. Presence of worms causes macroscopical and histopathological lesions in many organs of dead horses.