We investigate the light scattering characteristics of water droplet aerosols containing defined inclusions. The inclusions are either di-2-ethyl-hexyl-sebacate (DEHS) droplets or carbon-like particles located within an outer shell of water. For modeling the Mie theory of light scattering adapted to scattering from layered spherical particles has been applied assuming that the inclusion is placed centrally in the outer droplet. Experimental evidence obtained with inclusions having modal diameters in the range from 100 to 800 nm imbedded in water droplets is compared with modeled results. The presented data suggest evidently that the negligence of inclusions in droplets, especially of those with absorbing properties might affect a number of crucial issues such as quantification of the impact of atmospheric aerosols on radiative transfer in atmosphere, modeling of light propagation in aerosols, calibration of instruments based on the interaction of light with particles, or optical aerosol measurement. (C) 2004 Elsevier Ltd. All rights reserved.