Semen from males of a flightless strain was diluted with solutions having different salt concentration and pH, and held at 50–52°F for 3–7 hours, following which it was inseminated into White Leghorn females. Varying concentrations and proportions of Na2HPO4 and NaH2PO4· H2O were used in the diluents. Fertility was maximum when the freezing point depression of the diluent was between .607 and .639°C, but decreased gradually outside of this range. There was little difference in fertility between pH 6.47 and 7.95, but outside of this range there was a marked decline. The optimum pH appeared to be between 7.03 and 7.27. Motility was found to be an approximate measure of fertilizing ability with varying salt concentration and a poor measure when varying pHs were used. Hatchability was not adversely affected when eggs were fertilized by diluted, stored sperm. Submitted on July 1, 1957