A candidate gene, involved in the regulation of bone mass is the COLIA1 gene encoding type I collagen, the major protein of bone matrix. The disease per se, the age of its onset and treatment options might exert an impact on bone mineralization in survivors of childhood malignancy. We examined possible allelic influences of COLIA1 gene polymorphism on BMI, BMD spine and total body in 41 survivors (15 girls) of childhood cancer (the mean age 8.9 years). Genotype distribution was 33 (80.5%) SS and 8 (19.5%) Ss. There were no differences in SDS BMD and SDS BMI between patients with SS and Ss genotype. A tendency towards lower SDS values of BMD spine and BMI was observed (not significant). In conclusion, our preliminary observations suggest that COLIA1 genotype may affect bone accrual in a population treated for childhood cancer. Further investigations in a greater population are needed.