Cryptosporidiosis is a parasitic disease caused by a protozoan from the genus Cryptosporidium with cosmopolitan distribution and zoonotic potential. The objective of this work was to determine the occurrence of Cryptosporidium and helminthosis in Santa Ines sheep herd during dry and rainy season. This work was developed at the sheep's breeding sector from the Federal University of Piaui, located in Southern Piauí, Brazil. Fifty sheep kept in a semi-intensive system were used in the experiment using the method according Ritchie, Ziehl-Neelsen and Gordon and Whitlock. Cryptosporidium oocysts were detected in 36% of the animals tested, with 20 males exhibiting a percentage of 50% (10 animals) protozoan in the feces and 50% (10 animals) exhibiting negative results. Among the 30 tested females, 8 (26.6%) were positive and 22 (73.4%) were negative. Concerning the age, 24 animals (48%) were of 0-12 months old, with prevalence of 11 (46%) positive animals showing protozoan in the feces, and 26 animals (52%) between 13-48 months old. The rainy season showed the highest counting of eggs per gram of feces (EPG), reaching a mean value of 2250 thus, a high occurrence of Cryptosporidium was evidenced, with a higher infection degree in young male sheep, predominantly during the rainy season, when a higher EPG was observed.