INTRODUCTION: Retinoblastoma is the most prevalent intraocular tumor in children, commonly manifesting as leukocoria. Persistent fetal vasculature (PFV) is another cause of leukocoria, resulting from the incomplete regression of fetal eye blood vessels. The simultaneous occurrence of retinoblastoma and PFV in the same eye is extremely uncommon and presents significant diagnostic difficulties. CASE PRESENTATION: We present a case involving a 2-year-old girl with leukocoria and esotropia in her left eye. Clinical assessments, including biomicroscopy, ocular ultrasound, and magnetic resonance imaging, identified a retrolental mass with calcifications and a hyperechoic tubular structure, indicating the presence of both retinoblastoma and PFV. Enucleation followed by histopathological analysis confirmed these diagnoses. The histopathology revealed retinoblastoma with Homer-Wright and Flexner-Wintersteiner rosettes and signs of PFV, with persistent large vessels in the retrolental region. CONCLUSION: The coexistence of retinoblastoma and PFV in a single eye is rare and complicates the diagnosis of leukocoria. Comprehensive multimodal imaging is crucial for accurate diagnosis and effective management, tailored to the distinct needs of each condition. This case highlights the importance of detailed evaluation in pediatric patients with leukocoria to ensure correct diagnosis and appropriate treatment.