A detailed study of kerosene spray and spray flames is performed to investigate the spray structure using an air-assisted atomizer. A particle dynamic analyzer (PDA) is used to measure Sauter mean diameter (SMD), mean, and root-mean-square (rms) values of axial drop velocity, drop number density, and velocity-size correlations. Three representative flames are studied and measurements are made at three different axial locations from the nozzle, with and without combustion. A thermocouple is used to measure the average local temperature. Direct photographic technique is also employed to visualize the spray and flame boundaries. Detailed comparison of the spray structures in nonburning and burning conditions is presented. The presence of the flame greatly alters the spray structure, including the interaction between the two phases. Results indicate that the overall structure of an air-assisted spray flame is different from that of gaseous diffusion flames and is characteristically similar to internal group combustion mode where liquid and gas phase reactions coexist. In the primary combustion zone, however, the gas-phase reaction is dominant, exhibiting a sheath of combustion. A physical model of the structure in air-blast flames is also proposed and discussed.