Haemonchus contortus (H. contortus) is one of the most pathogenic gastrointestinal nematodes of sheep and goats. The present study was aimed to investigate the impact of H.contortus natural infection in sheep and goats. The haematological, biochemical, immunological and oxidative stress markers were estimated. Blood samples were collected from clinically infected animals for analysis. Abomasum examination was performed after slaughter the animals to confirm the presence of H.contortus adult worm. Parasitologically, H.contortus worms were detected and counted in the abomasum of infected animals. Haematological findings revealed that naturally infected sheep and goats exhibited microcytic hypochromic anaemia, leukopenia, lymphopenia and neutropenia with eosinophilia. H.contortus infection-induced hypoproteinemia, hypoalbuminemia, and hypoglobulinemia. Also, it markedly lowered the serum IgG&IgM and elevated serum IgE levels. Serum concentration of superoxide dismutase (SOD) was reduced, whereas lipid peroxidation (MDA) levels were elevated. However, serum levels of iron (Fe), zinc (Zn) and copper (Cu) were markedly lowered and the total iron-binding capacity (TIBC) was elevated. Finally, this work clears that H.contortus infection in sheep and goats induced alterations in haematological, biochemical and immune marker, with stimulation of oxidative stress, these results may be good and helpful for detect and diagnose of H.contortus infection in sheep and goats.