The glass transition temperatures of binary mixtures of polyamines and polyalcohols are investigated by differential scanning calorimetry (DSC). For all systems, the composition dependence of the glass transition temperature T-g shows clear maxima, in stark contrast to those of polyalcohol-polyalcohol mixtures reported previously. A thermodynamic analysis based on the entropy theory is carried out for(1,2-propanediamine), (glycerol)(1-x), and (1,2-propanediamine)(x)(1,3-propanediol)(1-x) systems. The composition dependence of T-g predicted from the entropy theory of regular solutions (regular solution model, RSM) is not able to reproduce the anomalous behavior, and the excess configurational entropies S-c(E) are negative and larger than 20 J K-1 mol(-1) in absolute value at the minima. The origin of the large value of S-c(E) is discussed With respect to the change of hydrogen bond network structure on mixing.