To correlate baseline spectral-domain optical coherence tomography characteristics with the number of as-needed intravitreal injections of ranibizumab over a 24-month follow-up period in eyes with neovascular age-related macular degeneration.Two hundred thirty-six eyes of 236 subjects with neovascular age-related macular degeneration treated with ranibizumab 0.5 mg pro re nata in the HARBOR study were enrolled. Baseline spectral-domain optical coherence tomography images were evaluated by certified reading center graders for specific morphologic features of the macular neovascularization lesion and surrounding retina. Baseline optical coherence tomography features and patient demographics correlated with the number of injections over the next 2 years.The mean number of injections in the 0.5 mg pro re nata group was 8.07 (median 8, 3-12) after 12 months and 14.25 (median 14, 3-24) after 24 months of treatment. After multivariate, linear, regression analysis, the only baseline parameter that was independently associated with a higher injection frequency at both 12 and 24 months was a greater baseline subretinal fluid thickness.A greater subretinal fluid thickness at baseline was associated with a higher frequency of pro re nata injections over 12 and 24 months in eyes treated with ranibizumab for neovascular age-related macular degeneration. These findings may be of value in counseling patients who are about to initiate therapy for macular neovascularization.