Two rates (0.4 mg/kg body weight/d and 0.6 mg/kg body weight/d) of a daily feed-through formulation of novaluron (Novaluron 0.67% active ingredient Cattle Mix), a newer benzoylphenyl urea insecticide, were evaluated for efficacy in controlling the larval stage of horn flies, Haematobia irritans (L.), house flies, Musca domestica L., and stable flies, Stomoxys calcitrans (L.), developing in cow manure. Both rates of feed-through novaluron, delivered consecutively for 10 d, reduced adult emergence of all three species when compared with the untreated control. The presence of deformed puparia indicated that novaluron had an insect growth regulator effect on the developing fly larvae. Both of the feed-through rates evaluated resulted in 100% reduction of adult stable fly emergence after the second day of feed-through treatment. The level of control efficacy observed against these three fly species make this feed-through formulation a candidate for use in an integrated livestock pest management program, particularly in confined cattle production situations where a feed-through product could be easily administered.