Matrix-assisted laser desorption/ionization (MALDI) has been employed for the determination of molecular weights of alpha- and beta-globins obtained from blood samples of healthy and diabetic subjects. Glycated species, originating from the reaction of glucose with the proteins, are easily evident. The MALDI measurements allowed one to distinguish between simple glycation and glyco-oxidation processes of haemoglobin. In fact, together with the products arising from simple glucose condensation on the two proteins, compounds at different oxidation levels were evident. Due to its high specificity, MALDI must be considered a valuable tool for diagnosis in the diabetes field.