This study concerns experimental investigation of the effect of gas to liquid mass ratio (GLR) on spatial Sauter mean diameter (SMD) distribution, drop size distribution, and near-nozzle spray structure in an airblast spray. A particle/droplet imaging analysis (PDIA) technique is used to measure SMD and drop size distribution at various points in the spray. The near-nozzle microscopic images of spray show the presence of large ligaments and liquid lumps at low GLR conditions. The primary atomization is almost complete within 5 mm below the nozzle tip for GLR 3 and above. Droplets with diameter more than 80 mu m are present for GLR 1 and 2 conditions. Uniform spatial SMD distribution in the span of 10 ?m is obtained for GLR higher than 3. A new empirical correlation to estimate SMD distribution in an airblast spray is proposed using nondimensional analysis and experimental SMD measurements. The correlation considers influences of operating condition and liquid properties on SMD distribution in airblast spray. The proposed correlation shows good agreement with the measured data.