A multistage dynamic flow dilution olfactometer allowing the delivery of precisely controlled stimuli over a wide concentration range is presented. Discrete concentration values, in the range 10(-6) to 5.6 X 10(-2) of the saturated vapor of an odorous compound, are obtained from two original concentration by combining 4 dilution stages. Short stimulus pulses, of a known and reproducible concentration and with short rising and falling times, are sampled from steady concentration levels. A programmable controller manages the olfactometer dilution stage selection, the odor stimulus switch and starts the peripheral devices required by the experiment. The programming of olfactometer function makes it an extremely flexible system for various experimental projects in olfaction.