Purpose: To describe an elderly woman who presented with a serous retinal detachment (SRD) as the first sign of Philadelphia- chromosome- positive acute lymphoblastic leukemia (Ph+ ALL). Design: Observational case report. Methods: A complete ophthalmic and systemic evaluation was performed on a 62- year- old woman because of decreased vision of 20/60 OD and 20/25 OS. Results: Fundus examination revealed a SRD involving the fovea. Fluorescein angiography disclosed multifocal spots of hyperfluorescence in the early phase, and diffuse subretinal accumulation of fluorescein in the late phase. She was diagnosedwith Ph+ ALL because of systemic findings. She underwent systemic chemotherapy and went into complete remission. Visual acuity improved to 20/20 in both eyes with resolution of the bilateral SRD. Conclusions: Our observations indicate that a sudden appearance of SRD, even in an elderly patient, warrants a thorough systemic screening for underlying leukemia. This is especially important, because prompt systemic chemotherapy can improve the visual acuity and the prognosis. Purpose: To describe an elderly woman who presented with a serous retinal detachment (SRD) as the first sign of Philadelphia- chromosome-positive acute lymphoblastic leukemia (Ph + ALL). Design: Observational case report. Methods: A complete ophthalmic and systemic evaluation was Results on Fundus examination revealed a SRD involving the fovea. Fluorescein angiography discloses multifocal spots of hyperfluorescence in the early phase, and diffuse subretinal She was diagnosed with Ph + ALL because of systemic findings. She underwent systemic chemotherapy and went into complete remission. Visual acuity improved to 20/20 in both eyes with resolution of the bilateral SRD. Conclusions: that a sudden appearance of SRD, even in an elderly patient, warrants a thorough systemic screening for underlying leukemia. This is especially importan t, because prompt systemic chemotherapy can improve the visual acuity and the prognosis.