PSA is currently being used to detect and monitor quantitatively the development of prostate cancer by serum levels of PSA, and PSA has also been found to be present in high concentrations in semen. The most common procedures for the forensic identification of semen have focused on the microscopic detection of sperm, acid phosphatase activity, and immunoelectrophoretic methods for the detection of PSA. Although these methods have been used for many years, there are problems associated with each method. In the current study, 14 fabric samples with stains and 12 fabric control areas that consisted of denim, cotton, and cotton blends were analyzed for acid phosphatase activity, spermatozoa, and PSA. The results show that the Hybritech Tandem-E PSA Immunoenzymetric Assay can be used to identify the presence of PSA that is of seminal origin in a biological stain. The use of this commercially available kit allows the forensic laboratory to perform a large number of simultaneous analyses. Thus, this method provides an alternative procedure for semen identification that is less labor intensive and therefore more cost-effective than conventional semen identification methods such as sperm identification. Furthermore, this kit is available in a microtiter plate format that allows even more automation. 2 tables and 12 references