A BESS-T-Scan analysis of cDNA COL1A1 and COL1A2 obtained by RT-PCR derived from five patients with sporadic forms of ostegenesis imperfecta was performed. The study was done in four patients with type I and one patient with type III OI. The analysis revealed the presence of structural changes in two regions of cDNA COL1A1 in two patients. No quantitative changes referring to COL1A2 gene were noted in any patient. The above analysis was the first application of the BESS-T-Scan technique in a molecular diagnosis of OI. The applied method seems to be useful and fulfil the basic criteria of the screening method to detect and locate mutations.