The YTTTC pentanucleotide short tandem repeat polymorphism HumCD4 was studied in an Italian population sample. PCR products were compared to an allelic ladder by manual PAGE and silver staining. A total of 6 alleles ranging from 5 to 12 repeats were represented in the analysed sample, of which 3 alleles (10, 6 and 5 repeats) were predominant and displayed a combined frequency of 0.91. Successful amplification was obtained from different sources such as blood and urine stains, teeth and paraffin embedded tissues. Results were also determined in cases of severely degraded DNA. We consider that the HUMCD4 polymorphism may be a useful tool for individual identification, paternity testing, population studies and have also employed this locus to monitor engraftment of bone marrow transplantation.