Milk powder deposition is an area of importance to the dairy industry as it affects the efficiency of the spray drying process. An unconfined yield test was used to measure the cohesion of dairy powders to determine the influence of powder composition, temperature, moisture content and particle size. As an index of cohesion, values of unconfined yield stress were obtained for whole milk powder (WMP) and skim milk powder (SMP). Dry WMP was found to be more cohesive than dry SMP with increasing temperature, which indicates the influence of fat in the cohesive mechanism in WMP. Particle size also affected the cohesion of dairy powders, cohesion being reduced as the particle size increased. The glass transition effect was isolated when testing for the effect of moisture by using a vibrated fluidised bed technique. This was highlighted by the change in the cohesion transition temperature between two WMPs with different moisture contents. An increase in moisture content, particularly above 6 wt% increased the cohesion of WMP, possibly as a result of the formation of liquid bridges; these results confirm the only other previous work reported in the literature.