The collagen type I alpha1 (COLIA1) gene encodes for a major bone protein and is a strong candidate for genetic control of bone mineral density (BMD). COLIA1 gene polymorphism is associated with reduced BMD and increased fracture incidence. The aim of this study was to analyze the relationship between COLIA1 gene polymorphism and BMD in Serbian women.The women were divided into groups according to their DEXA phenotypes. They included 39 osteoporotic, 36 osteopenic, and 33 women with normal BMD. Single nucleotide polymorphism (G to T substitution) within the Sp1-binding site in the first intron of the COLIA1 gene was assessed by polymerase chain reaction (PCR) followed by single-stranded conformation polymorphism (SSCP) analysis.The genotype frequencies for the whole group were 67.6% GG homozygotes, 24.1% GT heterozygotes, and 8.3% TT homozygotes and were not in Hardy-Weinberg equilibrium (HWE). Significant deviation from HWE was found only in the osteopenic group (p = 0.0007), where a higher number of homozygotes was found. Comparison of the allele frequencies showed no significant differences between three groups of tested women.The presence of the T allele in the genotype has no influence on BMD in the osteoporotic group of women. The observed deviation in the osteopenic group needs to be investigated further.