Abstract: Formation of hydroxymethylfurfural (HMF) during heat treatment and subsequent storage for 90 days of UHT treated and whole milk powder at ambient temperature increases significantly. Values of HMF were significantly higher at 60 and 90 days as compared to the values at 0 and 30 days storage in case of UHT treated milk with fresh milk as standard. The difference between 0 and 30 and 60 and 90 days storage were non significant. The values for the same type of milk but with distilled water as control were significantly different and increased at each time interval i.e. 0, 30, 60 and 90 days. Analysis of reconstituted whole milk powder during the entire storage period with fresh milk as control showed HMF values significantly different at each time interval. The values were significantly different from 0 to 60 days but were non significantly different from 60 to 90 days with distilled water as standard.