The purpose of this study was to determine the nature of the relationship between density of indocyanine green (ICG) and the activity of occult choroidal neovascular membranes (CNVM) in patients with age-related macular degeneration (AMD) using ICG angiography. Ten eyes of ten patients with AMD and associated CNVM formation were retrospectively classified into either active or silent group on the basis of clinical outcome. Density of ICG for ICG leakage of CNVM was retrospectively determined from baseline ICG angiograms using an image analysis system. The means of relative density of the two groups were significantly different at five minutes after injection of ICG (p = 0.02). Densitometric analysis with ICG angiography may enable the discrimination of active from silent CNVM in patients with AMD, and thereby, prove useful in guiding clinical decision concerning treatment of these patients.