Retinoblastoma (RB) is a genetically predetermined intraocular malignant tumor, common in childhood, initiated by a mutation in the retnoblastoma gene (RB1), located on the long arm of chromosome13 (13q14). The lack of information on the genetics of RB in Bukavu motivated this study, with the aim of presenting the spectrum of mutations. Materials and methods This is an analytical cross-sectional study of 10 individuals, including 5 RB carrier children and 5 parents. Their deoxyrubonucleic acid (DNA) was extracted and 11 exons within the RB1 gene were amplified by Polymerase chain reaction, sequenced and analyzed by various bioinformatics tools. Result All the children had unilateral RB, diagnosed mostly at an age ≥2 years, male gender predominated, history of RB was absent in all subjects. A total of 11 of the 27 most frequently mutated exons that make up RB1 had been analyzed. The types of deleterious mutations found in exons 8 and 20 alone, in the 5 children and one parent, were of the following types: missense (26.6% vs. 16.7%), deletion (11.1% vs. 50%) and insertion (66.7% vs. 33.3%), generally associated with a frameshift and a splice site change. Disruption of protein synthesis was observed in all the children and in only one parent. Conclusion The deleterious genetic mutations identified by the study were known. The study suggested additional studies, integrating environmental factors that are currently believed to be involved in the occurrence of RB.