Exposure of quail eggs 4 hr per day during the first 5 incubation days at 2450 MHz and in an exposure field of 30 mW/cm-2 and at an absorbed power of 14 mW/g does not cause any great change in body weight, observed gross malformations, rbc, wbc, hematocrit, hemoglobin, or differential wbc percentages. If small differences exist in these parameters due to microwave exposure, they are obscured by the large variability between individual quail. This variability is believed to partially result from changing blood values in the developing young quail, and the 2-day spread in ages at the time of sacrifice could account for some of the variability. The overall hatch percentages for the exposed and control eggs were approximately equal. A slight significant decrease (11%) in hemoglobin was noted in the birds irradiated on Day 2. Additional verification, however, is needed, because the observed change is less than the normal range of values observed in young quail. These data do suggest, however, that exposure of developing Japanese quail embryo to microwave radiation of the frequency and power density level used in this study does not preclude normal systemic development, hematologic differentiation, or the general hardiness of the hatched quail.