A colorimetric assay for the detection of PCR-products is described. The assay is based on amplification of DNA in the presence of digoxigenin-dUTP. After immobilization of the PCR products to a microtitre plate, amplified DNA could be detected colorimetrically. The sensitivity of this colorimetric assay was equal to gel-analysis allowing the detection of 100 fg of template DNA. Here, we show that it can be used to detect Mycobacterium leprae DNA in biopsy specimens from leprosy patients. The simplicity and the low degree of variation make this assay an alternative to gel-analysis.