Spray drying of liquid food droplets is one of the primary means of manufacturing food powders today. Modeling this process requires single-droplet drying modeling, and droplet size change during drying is one part of such modeling. Some experimental data of milk droplet diameter change at 20 and 30 wt are reported in literature. Data are not available at higher solid contents, which are of interest to the industry. We now report the experimental results of the effects of drying conditions on milk droplet size change (using projected area diameter as the parameter) using the glass filament technique, complimented by video imaging analysis software. Under the constant drying air conditions for solids content of 40 wt , and for both skim and whole milk, the droplet diameter changes were correlated using the previous model of Lin and Chen. With previous data together, the shrinkage coefficients were correlated against solids content.