A study was conducted to determine the effects of solid-liquid separation of liquid swine manure on ammonia emissions from lagoons. This determination was done at full-scale in two contiguous swine production units that had similar animal production management. One of these units was maintained as a control using the anaerobic lagoon treatment method. In the second production unit, solids were removed from liquid manure using an enhanced-polymer solid-liquid separation treatment prior to lagoon storage. The ammonia gas fluxes from both lagoons were measured simultaneously during a 10-month period (Feb.-Nov., 2004) using passive flux samplers. On average, the solid-liquid separation treatment separated 85% of total suspended solids (TSS), 60% of total solids (TS), 73% of chemical oxygen demand (COD), 81% of organic N, and 8% of total ammoniacal N (TAN) from the liquid entering the lagoon. Ammonia emissions from the anaerobic lagoon control totaled 12,542 kg N/yr (13,633 kg N/ha/yr). This compares to lower ammonia emissions of 3,426 kg N/yr (or 3,684 kg N/ha/yr) from the anaerobic lagoon treated with solid-liquid separation. Although water quality changes were modest in the treated lagoon with respect to the control, total annual NH3 emissions abatement in the lagoon with solid-liquid separation was 73% with respect to the anaerobic lagoon control. These results overall demonstrate that solid-liquid separation technologies can substantially reduce ammonia emissions from anaerobic swine lagoons.