The oviposition of stable flies,Stomoxys calcitrans(L.), was determined for several temperature and humidity conditions in the laboratory. Oviposition was greater and began at younger ages at the higher temperatures. Ovarian development and oviposition rates appeared to respond to temperature in the same manner as development of immature stages in previous work. Humidity did not appear to affect oviposition. The flies produced more eggs at a particular air temperature if the temperatures for adults and immatures were similar. A simple procedure for predicting oviposition rates in variable temperature regimes was developed.