Erythrocyte acid phosphatase (ACP1), also named low molecular weight phosphotyrosine phosphatase (LMW-PTP) is an enzyme involved in signal transduction pathways of tyrosine kinase receptor. The precise physiological role of ACP1 remains to be elucidated, however recent advancements suggest that it may play an important role in the control of cell proliferation. ACP1 is a highly polymorphic enzyme that has been investigated by case-control studies for decades. Initially based on protein electrophoresis, the phenotype of ACP1 is now detected by DNA-based techniques. Here, we report a new rapid single tube genotyping method for ACP1 by FRET based amplification and dual color melting curve analysis. This method does not require a post-procedure amplification process and allows unambiguous genotyping of 30 samples in less than 1 h.