The present study aims to evaluate the prevalence of gastrointestinal parasites in sheep of Biskra region according to age classes and to detect eventual zoonotic parasites. It included 372 sheep, females and males. 248 fecal sheep samples were coprologically examined and coprocultured, 119 being from adult sheep (≥ 12 months) and 129 from lambs (< 12 months). Also, 124 adult sheep were necropsied after the slaughter, focusing on the livers, lungs and intestines. The qualitative flotation technique was used by employing the McMaster microscope slides. All the statistics was done by using the SPSS 20. Prevalences were calculated according to age classes and parasites genera. Kendall test (p < 0.05) was applied to detect any correlation between total prevalence and parasite genera prevalences in adults versus lambs. The results showed that medium prevalence for five years in adults (63.02 %) was higher than in lambs (57.36 %). Coproscopy showed: coccidia, gastrointestinal strongyles, Nematodirus spp, Moniezia spp and Marshallagia spp. Coproculture showed Protostrongylus spp. and Dictyocaulus spp. Necropsy revealed Fasciola hepatica, Echinococcus polymorphus, Thysaniezia ovilla, Moniezia expansa, Cysticercus tenuicolis, Cysticercus ovis and Paramphistomum daubenyi. The diversity and simultaneousness of gastrointestinal parasites could have a negative impact on production parameters in infected sheep. The risks of contracting echinococcosis as a major zoonosis requires more respect of deworming programs in dogs and sheep and better vigilance in slaughterhouses.