Context:The most commonly injured body part for skiing has been found to be the knee. The rupture of the anterior cruciate ligament (ACL) was the most frequent diagnosis. ACL ruptures are determined by several extrinsic and intrinsic risk factors including those that are hormonal, neuromuscular, anatomical, or genetic.Objectives:To examine the association of both COL1A1 rs1800012 (+1245G/T) and COL1A1 rs1107946 (–1997G/T) polymorphisms, individually and as haplotypes, with ACL ruptures in recreational Polish skiers.Design:Genomic DNA was extracted from buccal cells donated by the subjects, and genotyping was carried out using real-time polymerase chain reaction.Settings:University laboratory.Participants:138 male recreational skiers with surgically diagnosed primary ruptures and 183 apparently healthy male recreational skiers not differing markedly in age or level of exposure to ACL injury.Main Outcome Measures:COL1A1 rs1800012 and COL1A1 rs1107946 polymorphisms.Results:There were significant differences in genotype distribution of the COL1A1 rs1800012 polymorphism between the ACL rupture group and the control group. The GG homozygotes were underrepresented in the ACL rupture group compared with the control group. There were no significant differences in genotype distribution or allele frequency of COL1A1 rs1107946 polymorphisms between the ACL rupture group and the control group. The G-G (COL1A1 rs1800012G and COL1A1 rs1107946G) haplotype was the most common. There were no significant differences in haplotype distribution between the ACL-rupture and control groups.Conclusion:The study showed that GG homozygotes were underrepresented in the ACL-rupture group compared with the control group, which suggests an association with reduced risk of ACL injury.