The Delmarva Peninsula on the Eastern Shore of Maryland ranks 4th in the nation in poultry production and generates 9,500 metric tons of poultry manure/litter per day. The poultry litter contains many macro and micro nutrients and is an excellent source of fertilizer. The litter also contains antibiotics, heavy metals, hormones and many microorganisms. Land application of this litter has been the only means of its utilization and disposal. With rainfall, surface water run-off (leachate), from land on which litter has been applied, reaches the Cheasapeake Bay from this region. This leachate with its high organic and inorganic salt contents and high biochemical oxygen demand can severely disrupt the aquatic life and cause fish kills. The objective of this research was to study the effect of simulated acid rain (pH 3, 4 and 5) on the toxicity of poultry litter extracts.