Background:-Osteoporosis is an important cause of morbidity in patients with β-thalassemia. The pathogenesis of reduced bone mineral density (BMD) is multifactorial. A range of genetics factors have been implicated in patients with osteoporosis. Polymorphism at the Sp1 binding site of the collagen type I A 1(COLIA1) gene is thought to be an important factor in development of osteoporosis. Objective:-is to study the relationship between SP1 polymorphism in the collagen type 1 alpha 1 gene and the development of osteoporosis in patients with Beta thalassemia. Methods:-A total of 40 patients with β-thalassemia(21 females &19 males)aged 6-18 yearsand 40 healthy subjects cross matched with age and sex. Serum osteocalcin, serum alkaline phosphatase, calcium and DEXA were examined in all patients. The COLIA1 Sp1genotypes (SS, Ss, ss) were measured by digestion using restriction enzyme (Bal1) of DNA amplified by the polymerase chain reaction (PCR). Results:-SS (G/G) genotype in β-thalassemia major was30.7% and in β-thalassemia intermedia was 49.4% and the Ss (G/T) genotype in βT Major was 55.63% and in βT intermedia was 50.6%, the ss genotype (T/T) type in βTM was 13.67% only. The difference was statistically significant (p= 0.040). There was highly significant difference between thalassemia major and thalassemia intermedia compared to control group as regard Ca, OC, ALP and DEXA (P= 0.000). Conclusions:-Detection base substitutions at the Sp1 binding site on the COLIA1 gene in early years considering an important role in preventing osteoporosis in children with beta -thalassemia.and early mangment of these patients.