Fluorescence time decay of human aorta has been measured at 380, 440, 480 nm using 320 nm excitation and time-correlated single photon counting technique. Fluorescence decay was found to be nonexponential at all emission frequencies. The normal and diseased sample showed significantly different fluorescence behaviors at 380 nm while this time decay difference was decreased in the fluorescence at 440 and 480 nms. The decay data were multiexponential and were analyzed with two exponential decay constants. The fluorescence decays were compared with and analyzed in terms of collagen and elastin.