Availability of nutrients in the soil is vital for proper plant growth. Amisorb^™ (polyaspartic acid), a synthetic protein, is used to increase nutrient availability to plants. The objective of this experiment was to determine the effectiveness of Amisorb^™ combined with different fertility treatments on fruiting and yield of cotton (Gossypium hirsutum). Data collected showed that Amisorb^™ provided no significant differences in yield, regardless of rate or fertility treatment. Total number of bolls and percent boll retention were decreased with the use of the rates of Amisorb™ examined in this study. Yield, total number of bolls, percent boll retention, number of reproductive nodes, and height increased significantly with increased fertilizer rates. In conclusion, at the rates tested, Amisorb^™ combined with nitrogen did not provide any beneficial effects on cotton growth.