The prevalence of different internal parasites in both diarrheic and clinically healthy sheep was studied on 157 sheep from different localities at Assiut governorate-Egypt during the period extended at the beginning of April till the end of September 2014. The animals were divided into 3 groups, according to the clinical signs (severe diarrhea, mild diarrhea and clinically healthy) and according to age wise (12 months). Fecal samples were collected and examined by concentration sedimentation-floatation technique. The results indicated that the prevalence rate of total internal parasitic infestation in sheep was 76.43% (120 out of 157). Concerning the total helminth prevalence rate; it was 47.13% (74/157), while the prevalence rate for coccidial infection was 49.04% (77/157). Mixed infection with helminthes and coccidia was recorded in 31 animals with a prevalence rate about 19.74%. The highest prevalence rates for helminthes infestation were recorded in the age group more than 12 months 64.93% (50/77) and in animals suffer from mild diarrhea 81.25% (52/64). While, the highest prevalence rates for coccidian infection were recorded in animals suffering from severe diarrhea 78.68% (48/61) and in the age group less than 3 months was 82.6% (38/46). Infestation by coccidian was not detected in any of the clinically healthy sheep. Twelve helminthes parasites were detected in the present study; Trichostrongylus spp < /em> was the predominant worm in examined sheep (19.74%).