The objective of the present study was to detect the allelic distribution of COLIA1 gene in beta thalassemia patients and its relation to bone mineral density (BMD).Material and method: The study included 25 beta thalassemia major patients. These patients were classified as thalassemia major on the basis of clinical examination, age of onset, rate of blood transfusion, and hematological data. Twenty unrelated normal persons who have no family history of thalassemia were taken as control group. Anthropometrical measures and measures of body composition were done to all thalassemic patients .Femoral and lumbar BMD was measured in all patients and control group using DXA. Assessment of the COLIA1 genotypes (SS, Ss, ss) was done using PCR amplification and restriction enzyme digestion (Bal1) of DNA amplified products to thalassemic patients and control group. Results: High prevalence of growth retardation was observed in beta thalassemia major patients in the form of short stature (36%), truncal shortening (48%) and under weight (8%).High prevalence of osteopenia and osteoporosis in thalassemia patients (68%). Significant negative correlation was noticed between duration of desferrioxamine intake (DFO) and femoral, lumbar BMD, between ferritin level and fat free mass %(FFM%) ,and between ferritin level and lumbar BMD in female thalassemic patients. Significant positive correlation was observed between age of starting DFO and sitting height SDS in male thalassemic patients. In thalassemic patients frequency of COLIA1 alleles was S (94%), s (6%). No association between COLIA1 gene polymorphism and BMD in the lumbar spine or in femur bone. In control, group allele frequencies were S (87.5%) and s (12.5%) and the s allele was associated with low femoral and lumbar BMD. Conclusion: high prevalence of endocrine and metabolic complications was observed in thalassemia major patients including growth impairment (stunting),osteopenia and osteoporosis .Iron overload, DFO toxicity beside the chronic anemia may be the causes of these complications. One of the genetic factors of osteoporosis is COLIA1 gene polymorphism and our results raise the possibility that genotyping of this polymorphism could be of clinical value in identifying the thalassemic patients at risk of osteoporosis and fractures.