The complex formation between cucurbituril and some amino acids and amino alcohols was studied by means of calorimetric titrations in aqueous formic acid (50% v/v). In the case of amino acids no influence of the number of methylene groups upon the stability constants could be observed. The complex formation is favoured by enthalpic and entropic contributions. During complex formation water molecules bound to carboxylic groups are set free. The situation changes completely in the case of amino alcohols. Reaction enthalpies and entropies are influenced by the number of methylene groups. The amino alcohol with three methylene groups forms the most stable complex. With increasing number of methylene groups the stability of the complexes formed decreases. For this decrease only entropic factors are responsible.