The pole/zero cancellation phenomenon is examined in the closed loop system resulting from the solution of the H-infinity control problem for time-varying systems. The unobservable and uncontrollable states are identified in the realization of the closed loop system associated with the general H-infinity control problem. These results are then used, in conjunction with previous results obtained by the authors on the pole/zero cancellation phenomenon in time-varying systems to identify pole/zero cancellations in two specific types of H-infinity control problems. These results generalize the work of Sefton and Glover for time-invariant systems.