In present research study, three experiments were launched during January 2011 to December 2011. Experiment I, Epidemiology: A total 1200 faecal samples (100 per month) were collected from farmers Bibrik-sheep (either sexes, 1-5 years old) and analyzed for nematodes prevalence. Experiment II, Sero-diagnosis: The sera samples of healthy and nematodes infected sheep were analyzed through ELISA. Experiment III, Therapeutic trial: comparative efficacy of herbal and synthetic anthelmintics was determined. Results showed that overall 40.25% Bibrik-sheep were infected with nematodes. Five nematode genera were recorded with higher prevalence of Haemonchus (10.42%) followed by Strongyloides (8.75%), Trichostrongylus (7.33%), Nematodirus (6.92%), and Trichuris (6.83%). The older age ewes presented higher nematodes prevalence. These five genera of nematodes were prevalent throughout the year. However, two peaks of nematodes prevalence i.e. March/May and August/December 2011 were observed. The level of nematodes infection was mostly low (< 2000 EPG) and did not impair the sheep productivity seriously. Haemonchus and Trichuris positive samples, based on coprological examination indicated 100% positive sensitivity for each genus of nematode by the ELISA, based on crude somatic antigen, while based on excretory antigen, showed lower (92%) sensitivity. The higher (86-100%) reduction of EPG was recorded in sheep treated with Ivermectin, while lower (68-96%) with Atreefal deedan.