Absorption spectra of alkali cyanide molecules, MCN (M = Na, K, Rb), in the gas phase were measured in the energy range from 4.1 to 11.4 eV by use of synchrotron radiation. A windowless absorption cell was specially, designed for the measurement of absorption spectra at temperatures less than 1000 K. A major portion of the spectra was ascribable to electronic transitions to repulsive states and to excited ion-pair states of MCN. The bands at 8.0, 7.4, and 7.1 eV in the spectra of NaCN, KCN, and RbCN, respectively, are associated with the transitions to the lowest excited ion-pair states of MCN correlating to M(+) + CN- ((3) Sigma(+)). The rest of the bands having a fwhm of about 1 eV were assigned to bound-free transitions to repulsive Rydberg states correlating to M(S-2,P-2) + CN(X(2) Sigma(+),A(2) Pi,B-2 Sigma(+)). The bands associated with the higher excited ion-pair states seem to be piled up with the bands associated with Rydberg states higher than these repulsive Rydberg states. It seems that the repulsive Rydberg states and the excited ion-pair states are related to the dissociative and the predissociative states in the reactions of MCN with metastable rare gas atoms, respectively.