Over the past several years there has been growing concern about the presence of antibiotics in ground and surface waters in the United States and Europe. While antibiotics are typically found in low concentrations, there is little information about their long-term effects on human health and the environment. Antibiotics are excreted largely unaltered and make their way through wastewater treatment plants and septic systems, which are not designed to remove these compounds from the effluent. Currently there are no data available on the fate or effects of antibiotics in septic system leachfield soil, and there is no information on alternative treatment processes that may potentially enhance the removal of antibiotics from septic system effluent. We present data from an addition experiment where we examined tetracycline removal and water quality in conventional and aerated septic system leachfield soil at the pilot scale. Research was conducted at a laboratory facility built adjacent to a two-family home in southeastern Connecticut. All effluent from the septic tank was diverted to a pump station located above the laboratory, and dosed to a series of six lysimeters. The lysimeters were dosed four times a day for ten days with wastewater containing 5 mg tetracycline/L. Three of these lysimeters were vented to the home's leachfield (LEACH), while the headspace of the other three was pumped with ambient air to maintain an oxygen level of approximately 21% (AIR). Only one replicate in the AIR treatment had a lower pH as a result of tetracycline addition. Total nitrogen and phosphorous removal in AIR and LEACH treatments was unaffected by the addition of tetracycline. There were no apparent effects of tetracycline on concentrations of nitrate, ammonium, or phosphate in drainage from LEACH or AIR lysimeters.