The objective of this study was to evaluate the association between serum vitamin D deficiency and age-related macular degeneration (AMD) in Koreans through a clinical case–control pilot study. The study included 96 patients: 30 with late AMD, 32 with early AMD, and 34 normal controls. The patients with late AMD were divided into 2 subgroups based on the presence or absence of subretinal fibrosis on optical coherence tomography (OCT) images. We measured 25-hydroxyvitamin D levels in the serum of all patients during the same season to rule out seasonal variation of serum vitamin D level. Serum vitamin D deficiency was defined as a serum 25-hydroxyvitamin D level below 20 ng/mL. Serum vitamin D deficiency had a tendency to increase the risk of early AMD, although with borderline significance [odds ratio (OR) = 3.59; 95% confidence interval (95% CI) 0.95–13.58; P = .060]. It was significantly associated with a greater risk of late AMD (OR = 3.61; 95%CI 1.04–12.51; P = .043). Among the 2 subgroups of patients with late AMD, those with subretinal fibrosis present on the OCT images showed a greater risk of serum vitamin D deficiency than the normal controls (OR = 7.54; 95% CI 1.34–42.51). However, there was no significant association between serum vitamin D deficiency and late AMD without subretinal fibrosis (OR = 1.89; 95% CI 0.40–8.92). Serum vitamin D deficiency may increase the risk of early and late AMD in Koreans, and may also be associated with subretinal fibrosis in this population.