Abstract Maltose is used in various forms in the food and pharmaceutical industries. Maltose syrups produced by enzymatic starch conversion usually contain impurity sugars, e.g. glucose, maltotriose, and higher saccharides, which affect the solubility of maltose. Using a simple refractometric technique, solubility data for the pure and impure maltose systems were determined. Glucose and maltotriose were found to decrease the equilibrium concentration of maltose but increase the total dissolved solids concentration.