Ammonia-nitrogen flux (NH3-N = (14/17)NH3) was determined from six anaerobic swine waste storage and treatment lagoons (primary, secondary, and tertiary) using the dynamic chamber system. Measurements occurred from autumn 1998 to early spring 1999, and each lagoon was examined for approximately one week, Analysis of flux variation was made with respect to lagoon surface water temperature (~15 cm below the surface), lagoon water pH, total aqueous phase NHx(=NH3 + NH4+) concentration, and total Kjeldahl nitrogen (TKN). Average lagoon temperatures (across all six lagoons) ranged from approximately 10.3 to 23.3 C. The pH ranged in value from 6.8 to 8.1. Aqueous NHx concentration ranged from 37 to 909 mg N l-1, and TKN varied from 87 to 950 mg N l-1. Fluxes were the largest at the primary lagoon in Kenansville, North Carolina, USA (March 1999) with an average value of 120.3 micro g N m-2 minute-1, and smallest at the tertiary lagoon in Rocky Mount, North Carolina (November 1998) at 40.7 micro g N m-2 minute-1. Emission rates were found to be correlated with both surface lagoon water temperature and aqueous NHx concentration. The NH3-N flux may be modelled as ln(NH3-N flux)=1.0788 + 0.0406TL + 0.0015([NHx]) (R2=0.74), where NH3-N flux is the ammonia flux from the lagoon surface in micro g N m-2 minute-1, TL is the lagoon surface water temperature in degrees C, and [NHx] is the total ammonia-nitrogen concentration in mg N l-1.