Alternaria macrospora Zimm. is a widespread foliar pathogen of cotton (Gossypium hirsutum L.) found throughout most production regions of the world.  The objectives of this study were to evaluate the impact of A. macrospora on various aspects of cotton production.  Samples were collected from six locations to compare cotton yield and fiber quality between healthy and infected areas.  Seed and lint yields, and selected fiber properties were significantly lower, and leaf grades significantly higher from infected areas.  As a result the overall crop value was reduced by approximately $732 ha^-1 when infected with A. macrospora.  Additional experiments are currently being conducted to examine the potential for transmission of A. macrospora on seed, and to evaluate the efficacy of selected seed treatments on growth and development of A. macrospora.  Results from this study will provide cotton producers with valuable information that can be used to manage this disease more efficiently in the future.