Efficacy of risedronian in osteoporosis therapy in connection with polymorphism of osteoprotegerin gene (OPG) was observed in our study. We assessed 49 women with postmenopausal osteoporosis on basis of measurment of femoral neck bone density before treatment of risedronian and after 12 months of therapy. Our study population used calcium and vit. D therapy as well. Efficacy of osteoporosis treatment was assessed as presence or lack of bone fractures. Investigation of polymorphism of OPG gene in exon 1 was provided with PCR, SSCP. Other polymorphisms were genotyped by RFLP. On the basis of genetic investigation our study population wad divided on 3 groups: group with CC-allele, CG-allele, GG-allele. After one year observation of risedronian therapy we noticed the highest increase of bone density only in CG- allele group and the smallest increase in CC-allele group. During our study bone fractures was observed in 2 patients – 1 from CG-allele group, 1 from GG-allele group. In our study no statistically significance of risedronian therapy in connection with polymorphism of OPG gene in postmenopausal osteoporosis was found.