Abstract: Background: Measuring of particle size, particle size distribution, viscosity and colour of powder is essential as it is directly related to powder behaviour and physical properties. Materials and Methods: In this study, physical quality parameters of nonfat dry milk (NFDM) and skim milk powder (SMP) including, particle size, particle size distribution at diameters d10, d50 and d90 in a cumulative size distribution, colour and viscosity were determined. Low, medium and high heat NFDM/SMP samples from US domestic producers were utilized. Results: Original powder samples had significant variations in lightness value L* (93.85-96.37) as well as b* value (12.32-17.99) based on the product source. The particle size in volume weighted mean, D [4, 3] of milk powders showed significant variations with a range of 29.32-94.24 μm. Significant differences in the viscosity of reconstituted milk were found with high heat treated powders having greater viscosity. Conclusion: Differences were noted between processors indicating differences in processing conditions between manufacturers, rather than the actual type of milk powder product.