In order to identify cross-culture contamination of cell lines, we applied DNA fingerprinting using variable number of tandem repeat (VNTR) loci and short tandem repeat (STR) loci amplified by polymerase chain reaction (PCR) instead of a radioisotope labeled multilocus probe. Eleven cell lines were used for the Apo B and D1S80 loci detection, and twelve cell lines were examined in the Y-chromosome analysis. The data obtained from the sister cell lines NALM-6 and B85, two MOLM-1 cultures from two cryopreserved tubes, and four subclones of BALM-9 and its sister cell line BALM-10, displayed clear and distinct bands of each PCR product for both Apo B and D1S80. Detection of a Y-chromosome DNA sequence is another very informative marker for the identification of cell lines, if the Y-chromosome is present. We examined eight cell lines for the expression of four STR loci; the data thus generated were compared with the results previously reported from other laboratories. The resulting electrophoretic banding patterns showed that our "home-made" STR detection system is a useful and efficient tool for the authentication of cell lines. PCR detection of VNTR and STR loci represents a simple, rapid and powerful DNA fingerprinting technique to authenticate human cell lines and to detect cross-culture contamination. This PCR technique may be used in lieu of the more time-consuming, labor-intensive and radioactive Southern blot multilocus method.