Microsatellites of the X-chromosome have been increasingly studied in recent years as a useful tool in forensic analysis. This review describes some details of X-chromosomal short tandem repeat (STR) analysis. Among them are: microsatellites, amplification using polymerase chain reaction (PCR) of STRs, PCR product evaluation, PCR product purification, separation and detection, data analysis of STR by Identity Software, locus information and allele frequencies for X-chromosomal STR in different populations (DXS101, DXS7423, DXS8377, DXS6789, DXS6807 genetic loci) and advantages of X-chromosomal micro-satellites. In forensic casework and DNA databases, polymorphism in STR is important as a forensic genetic marker.