PURPOSE: To determine the association between cystoid macular edema and vascular endothelial growth factor concentration in the aqueous humor and plasma of uveitis patients. METHODS: Cross-sectional study. Vascular endothelial growth factor concentrations were measured by enzyme-linked immunosorbent assay in the aqueous humor of 20 uveitis patients (9 with and 11 without cystoid macular edema), and in the plasma of 40 uveitis patients (20 with and 20 without cystoid macular edema) and 20 healthy volunteers. RESULTS: Mean aqueous humor vascular endothelial growth factor concentrations for uveitis patients with and without cystoid macular edema were 152.3 and 109.5 pg/ml, respectively, P = .044. Mean plasma vascular endothelial growth factor concentrations in uveitis patients with and without cystoid macular edema and in healthy volunteers were 32.2, 29.6, and 55.0 pg/ml, respectively. Uveitis patients had lower plasma vascular endothelial growth factor levels than did healthy volunteers, P = .0002 CONCLUSION: In uveitis patients, vascular endothelial growth factor concentration is increased in the aqueous humor of eyes with cystoid macular edema. It may be useful to investigate vascular endothelial growth factor antagonists as a treatment for uveitis-associated cystoid macular edema.