Purpose: The purpose of this study was to assess the effect of early diagnosis by physicians on outcome of retinoblastoma. Methods: This was an observational case series in which the records of 36 patients with retinoblastoma were reviewed. The age at onset of first symptoms and diagnosis, identity of the individual who first recognized an abnormality, treatment, and outcome were analyzed. Results: Twenty-two patients had unilateral retinoblastoma. Both eyes were preserved in only 2 of these patients, both of whom had abnormalities first noted by their pediatricians. Fourteen patients had bilateral retinoblastoma. Both eyes were preserved in the 5 bilateral patients who were monitored from birth with serial examinations under anesthesia because of family histories of retinoblastoma. Enucleation of at least 1 eye was required in 8 of the 9 bilateral patients whose families first noted abnormalities. Enucleation of at least 1 eye was required in 27 of 28 patients (96%) in whom abnormalities were first noted by parents. Conclusion: In this series, the only patients with unilateral retinoblastoma who did not require enucleation were those in whom pediatricians, rather than family members, first noted ocular abnormalities. Both eyes were preserved in all patients with bilateral retinoblastoma who underwent serial examinations under anesthesia because of family histories of retinoblastoma. The prognosis for retinoblastoma appears to be greatly improved when physicians initially detect abnormalities. Educational efforts directed at early detection of retinoblastoma by pediatricians and other primary care providers should be encouraged.