Purpose: To evaluate the age- and gender-specific prevalence of early and late age-related macular degeneration (AMD) in a Portuguese population-based sample. Methods: All patients aged ≥55 years of a Portuguese primary health-care unit were recruited for a cross-sectional population-based study. Responders underwent complete ophthalmological examination and digital fundus imaging. Early and late AMD was defined according to the International Age-Related Macular Epidemiological Study Group Classification, and the adopted staging for AMD was the same as that used in the Rotterdam study. The age- and gender-adjusted prevalence of early and late forms of AMD was calculated. Results: Of the 4,370 eligible subjects, 3,000 underwent study procedures (68.6% response rate) and 2,975 were included in the analysis; they had a mean age of 68.9 ± 8.6 years. The overall prevalence of early and late AMD was 15.53% (95% CI 14.25-16.88) and 0.67% (95% CI 0.41-1.04), respectively. Neovascular AMD (NV-AMD) and geographic atrophy (GA) accounted for 0.44% (95% CI 0.23-0.75) and 0.27% (95% CI 0.12-0.53) of individuals, respectively. The highest prevalence of advanced AMD was among those aged ≥75 years (1.13% for NV-AMD; 0.63% for GA). Conclusions: To our knowledge, this is the first AMD epidemiological study in a Portuguese population. The early forms of the disease had a similar prevalence to that of other large-scale population-based cohorts, but late AMD was less frequent than previously reported.