The article presents a study of mutation spectrum of RB1 gene in South Korean patients with retinoblastoma, the most common form of childhood intraocular tumor. It involved extracting of DNA from peripheral blood leukocytes and screening of RB1 gene mutations through sequence analysis of exons using an ABI 3730 analyzer and multiple ligation probe-dependent amplification (MLPA) method. The study reveals high detection of germline mutations with sporadic bilateral retinoblastoma.