Shorttitle Haemonchus is the most prevalent and highly pathogenic nematode of sheep and goats. A study was conducted to determine the prevalence, morphological characteristics and efficacy of albendazole and tetramisole against Ogaden isolate of H. contortus from August 2003 to March 2004. The overall prevalence of Haemonchus species was 91.23% and 82.93 % in sheep and goats respectively. Whereas 37.72% and 40.24% prevalence of Trichostrongylus axei was recorded in sheep and goats respectively. In sheep female Haemonchus worms were categorized as 49.49% linguiform, 28.51% knobbed and 23%...