The Hydrophile-Lipophile-Balance (HLB) numbers were evaluated on the basis of three different, commonly used methods of determination and calculation, in a series of lauric, resp. stearic acids and lauryl alcohol oxyethylenation products prepared by an alkali-catalyzed reaction in a similar scale of hydrophobe: ethylene oxide molar ratios. The results showed that, due to the different principles of the used methods, the HLB numbers were obtained with a great variance, limiting their use as parameters for estimation of the application effectiveness of non-ionic surfactants of the polyoxyethylene type. The HLB concept was not found able to consider the complicated composition of the studied types of surfactants and to provide relevant information in the already mentioned sense.