X-chromosome markers have become a useful set of markers of choice when certain complex kinship cases need to be unravelled. The Argus X-12 kit allows the co-amplification in a single PCR reaction of 12 X-chromosome short tandem repeats located in four linkage groups. A number of 507 unrelated individuals from Greenland, Denmark and Somalia together with two generation families were typed using the Argus X-12 kit. Silent alleles for the DXS10148 and DXS10146 systems were observed in males, mostly from Somalia. High levels of intrapopulation variability and therefore high forensic parameter values were calculated for the three studied populations. The population in Greenland showed a significantly lower intrapopulation variability and a high genetic differentiation compared with 13 other populations. Significant levels of linkage disequilibrium were observed between markers belonging to the same linkage group, mainly in the populations in Greenland and Somalia. Family studies allowed the calculation of mutation and recombination frequencies. A higher male versus female mutation rate was obtained, with an average value of 3.3¿×¿10(-3). Recombination fraction calculations performed on two generation families showed, as previously described, a not complete independence between X-chromosome linkage groups 3 and 4.