The catalytic activity of new hollandite compounds was investigated for the selective reduction of nitrogen monoxide (NO) with propene (C3H6) in the presence of high concentrations of oxygen. The well crystallized K1.8Ga1.8Sn6.2O16 hollandite (KGSO), a new compound of hollandite, showed catalytic activity in this reaction, and the K(x)M(y)Sn(8-y)O(16) (M=Zn, Fe, Co) hollandites were also active. These well crystallized hollandite catalysts displayed a certain relationship between the amount of nitrogen monoxide desorbed from the catalyst’s surface and the selectivity of the catalytic reaction, and hence it is suggested that the selectivity could be designed for this series of catalysts.