The powdered milk market is determined by consumer demand. Studies have shown that up to 37% of Polish society has problems with lactose digestion. In Poland, approximately 1.5% of infants and children and 30-37% of adults suffer due to a lack of β-D-galactosidase. Only lactose-free milk may replace mother’s milk in infants with this disorder. Knowledge of powdered milk properties is the basis for ensuring safety at each stage of a product’s life, which is of particular importance for infants – a very sensitive group of consumers. The objective of the paper was a comparative assessment of the sorption properties of full-fat lactose-free powdered milk (MB) and a standard variety (ML) of the same brand. It was assumed that modified powdered milk without lactose would substantially influence both the functional properties and utility characteristics of powdered milk. The experiment was carried out with Enfamil Premium 1 infant milk (abbreviated as ML) and Enfamil 0-Lac (abbreviated as MB) purchased in a pharmacy located in Gdynia. The study included the following components: measurements of water content and water activity, mapping adsorption isotherms at 20°C and 30°C, mathematical description of adsorption properties with GAB model, estimation of specific surface area and of dimensions and capacity of capillaries in the tested material. The examined products differed in their chemical composition, including water content. A different chemical composition substantially impacted the sorption properties of the investigated powdered milk varieties. The replacement of lactose with glucose syrup in the MB product eliminated the crystallisation phenomenon and determined the integrity of isotherms throughout the entire water activity range. The tested products also differed in microstructural surface parameters which determined the powdered milk utility characteristics affecting susceptibility to rehydration and shelf-life.