Odor emission rates and characteristics were evaluated at two commercial swine nurseries in Indiana during the months of March, April, and May. The nurseries, housing 94 to 250 pigs, were mechanically ventilated with long-term manure storage pits under wire floors. Incoming ventilation air at one of the nurseries was tempered in a heated hallway. An eight-member odor panel evaluated odor concentration with a dynamic olfactometer and odor intensity and hedonic tone at full strength. The odor concentration of incoming ventilation air ranged from 7 to 85 odor units per cubic meter (OU m(-3)) and averaged 18 OU m(-3). It ranged from 94 to 635 OU m(-3) and averaged 199 OU m(-3) in the ventilation exhaust air The mean odor emission rates of the two nurseries were 18.3 and 62.5 OU s(-1) AU(-1) (1.1 and 2.7 OU s(-1) m(-2)), respectively. The overall mean odor emission rate was 34 OU s(-1) AU(-1) (1.8 OU s(-1) m(-2)). The measured emission rates are expected to be lower than those that follow stringent panel sensitivity requirements not currently required by olfactometry standards in the U.S.