A reliable, efficient, and accurate detection method for presence of the endophytic fungus Neotyphodiurn coenophialum (Morgan- Jones and Gams) Glenn, Bacon, and Hanlin comb. nov. in tall fescue (Festuca arundinacea Schreb.) seed and plant tissue would be beneficial for tall fescue breeding and seed lot analysis. This experiment was conducted to determine the accuracy, reliability, and reproducibility of the Phytoscreen Neotyphodium immunoblot detection kit (Agrinostics Ltd. Co., Watkinsville, GA). Tissue immunoblot was compared with histological staining followed by microscopic analysis on tall fescue tillers from a greenhouse grow-out test, field grown spaced plants, established field paddocks, and different tall fescue seed lots. Endophyte-infected and endophyte-free tall fescue populations were evaluated by both methods. Results obtained by both methods were similar regardless of the infection level of the population, type of tissue assayed, or the technician that conducted the assay. The immunoblot detection kit was accurate and reliable and readily accommodated large numbers of samples.