The paper presents a study of the cyclotron waves in a plasma column enclosed in a conducting cylinder and placed in an axial static magnetic field. The cutoff frequencies of the waves are investigated with special reference to the role of the plasma radiusain the wave propagation. The cyclotron modes discussed cover all the possible types, namely, circularly symmetricCommodes and asymmetricCnmmodes withn?1, eachCnmmode being split into two, designated asC−nmandC+nmmodes, corresponding to two different polarizations of the field components. The upper and lower limits of the cutoff frequencies of the various modes asatends to zero and infinity, respectively, are derived. It is found that cyclotron modes can broadly be divided into the following two categories: (1)C+n1modes, the limiting cutoff frequencies of which are the electron cyclotron frequency &ohgr;ceand lower hybrid frequency &ohgr;lh, and (2) modes other thanC+n1modes, the limiting frequencies being the upper hydrid frequency &ohgr;uhand a frequency &ohgr;0which is a function of electron and ion plasma frequencies, &ohgr;peand &ohgr;pi, as well as electron and ion cyclotron frequencies, &ohgr;ceand &ohgr;ci. The modes belonging to the first category represent, in all cases, forward waves while those of the second category may represent backward or forward waves, depending essentially onaif &ohgr;peand &ohgr;ceare kept constant. The critical radii at which the change takes place for the lowest‐order modes are derived. The effect of plasma ions on the propagation of theC+n1modes is found to be considerable ifais sufficiently large. For other modes the effect can be considerable if bothaand &ohgr;cehave sufficiently high values.