OBJECTIVE: In this study, we focused on observation of the genetic polymorphisms of the OPG genes G1181C (rs2073618) and C290T (rs9525641), their interactions with biochemical markers and anthropometric parameters in groups of postmenopausal Slovak women (Roma and non-Roma, n = 311). PATIENTS AND METHODS: Genomic DNA was extracted and purified from peripheral blood leukocytes by the kit Ultraclean® Blood non-spin® (Carlsbad, CA, USA) using a standard protocol. Genotyping was performed by the TaqMan SNP genotyping assay. Biochemical markers were measured by the Cobas e411 (Roche Diagnostic, Tokyo, Japan) and Cobas Integra400 plus (Roche Diagnostic, Rotkreuz, Switzerland) analysers. RESULTS: We recorded a higher frequency of the T allele in the C290T polymorphism of the non-Roma control group (53.846%), in Roma groups: control (T - 56.618%) osteoporotic (T - 51.471%). In the G1181C polymorphism, the CC genotype occurred more in the osteoporotic group (34.286%) compared to the control group (27.885%). In the group of postmenopausal Roma women, a statistically significant difference (p<0.05) was found between osteoporotic and control in the biochemical parameters' osteocalcin, C-terminal telopeptide I, and age. Statistically significant differences (p<0.0001) were also found in bone mineral density and T-score. The high odds ratio suggests the association of G1181C with osteoporosis. A close relationship was found between haplotypes, BMD, T-score, and IL-6 in control; and BMI, WHR, T-score, and osteocalcin in osteoporotic groups of Roma and non-Roma women. CONCLUSIONS: The results point to differences in the occurrence of genotypes and associations of haplotypes with the manifestation of osteoporosis in Roma and non-Roma women. However, a larger number of samples is needed to determine whether or not there are differences between the Roma and non-Roma populations.