The genetic variability, haplotype profile and ethnic differences of MDR1 polymorphisms in healthy Roma and Hungarian populations were analyzed and the results were compared with those of other populations available from the literature. Healthy subjects (465 Roma and 503 Hungarian) were genotyped for C1236T, G2677T/A and C3435T variants of MDR1 by PCR-RFLP assay. Differences were found between the Roma and Hungarian populations in the frequencies of MDR1 1236 CC (20.7 vs. 33.2%) and TT genotypes (30.8 vs. 21.9%), in T allele frequency (0.551 vs. 0.443) (p < 0.002), and in 3435T allele frequency (0.482 vs. 0.527, p < 0.04). Furthermore, the frequency of CGC, CGT and CTT haplotypes was significantly higher in the Hungarian population than in Roma (41.4 vs. 35.3%, 9.04 vs. 6.02% and 2.88 vs. 1.08%, respectively; p < 0.009), whereas the frequency of TGC and TTC haplotypes was higher in the Roma population than in the Hungarian (7.31 vs. 1.68% and 6.67 vs. 2.08%, respectively; p < 0.001). The prevalence of MDR1 polymorphisms in the Hungarian population is similar to that of other European populations; however, some differences were observed in the haplotype structures. In contrast, the Roma population differs from Hungarians, from Caucasians and from populations from India in the incidence of MDR1 common variants and haplotypes.