Pseudomultiplicity of periodic states in pressure swing adsorption (PSA) is illustrated with a simple cycle. Pseudomultiplicity in PSA is defined by the existence of at least two different periodic states for a single PSA operating specification, such as fixed sorbent productivity, while product purity or product recovery may vary. Non-isothermal behavior, number of components, isotherm nonlinearities, and cycle complexity are considered requirements for conventional multiplicity in PSA, defined by different periodic states depending only on the initial condition of the beds, for the same input variables. The examples presented here, obtained with a simple model, show that pseudomultiplicity in PSA is neither a consequence of system nonlinearities described above nor the result of wave interactions due to cycle step complexity.