Amending poultry litter with aluminum sulfate (alum) reduces phosphorous (P) runoff and ammonia volatilization but its effects on soil pH are not completely researched. Greenhouse pot experiments with cotton (Gossypium hirsutum L.) and soybean (Glycine max. L. Merr) as test crops were conducted with a sandy loam (Fine-loamy, siliceous, semiactive, thermic Typic Paleudults) soil, that was adjusted to pH's of 4.5, 5.0, 5.5 and 6.5 using fine Ca(OH)₂. The objective was to determine if poultry litter amended with aluminum sulfate (alum) or ferrous sulfate at 0, 10% and 20% by weight affected soil pH, soil exchangeable aluminum and plant aluminum concentration when applied to meet N requirement of the crop. Application of non-amended litter and litter amended with 10% alum increased soil pH on all treatments. Application of litter amended with alum or ferrous sulfate at 20% reduced soil pH and increased soil exchangeable Al extracted with 0.01M CaCl₂. The increase in soil exchangeable Al and reduction in soil pH were greater for soils with pH of 4.5 and 5.0 than for soils with higher pH. Amendments significantly increased shoot Al concentration for plants grown in soil with pH of 4.5 and 5.0. The application of alum or ferrous sulfate at higher rates to soils with pH less than 5.5 has detrimental effects on the soil and plant and is of environmental concern.