Abstract: The effect of diet and density on the fecundity of adult houseflies in the pilot scale production of housefly larva was studiedA diet of brown sugar and milk powder was found to increase the fecundity of adult houseflies, and vegetable juice was found to be a helpful additiveThe fecundity was maximal （9.68 ovum/ind·d） at a moderate adult density（5.973 ind/m³）. The greater the adult density，the more stable the fecundity and the higher the total ovum number in the experimental enclosure. The peak of fecundity was reached about four days after oviposition began and was maintained for 3-5 days. A week later the fecundity had decreased markedly. After the oviposition peak had passed，the present population was killed，and another population already at the peak of oviposition was introduced. The fecundity was maintained continuously at a high level，which is an important aspect in artificial rearing

Key words: housefly larva, pilot scale production, adult housefly fecundity