Haemonchosis is one of the most important parasitic diseases due to its economic effect on the productivity of small ruminants. Accordingly, there is a significant need for the development of accurate immunological assays for early diagnosis. Little is known about coproantigen's dynamics in the feces of Haemonchus contortus (H. contortus)- infected sheep before egg shedding. In this study, two immunodiagnostic techniques were used:  antigen capture-Enzyme Linked Immunosorbent Assay (ELISA) and Enzyme-Linked Immunoelectrotransfer Blot (EITB). At 5-8 days post infection (DPI), antigen capture- ELISA detected H. contortus coproantigen in feces of the experimentally infected lambs. Diagnostic detection of the antigen using capture ELISA was recorded four days earlier than detection with indirect ELISA. EITB was more accurate in the early detection of coproantigen in fecal supernatants at 2^nd DPI. Two specific polypeptide bands of 42 and 126 KDa strongly reacted with the sera of experimentally infected lambs. Additionally, two specific polypeptide bands of H. contortus coproantigen with molecular weights of 54 and 59 KDa might be considered a reliable parameter in detecting the early phase of infection before egg shedding. Reactivity against these bands was observed beginning with the 8^th DPI and lasting until the experiment ended. In conclusion, H. contortus coproantigen could be used as a diagnostic antigen in sheep to detect haemonchosis during the prepatent period.