A flow rejection algorithm for the dynamic resource reservation protocol (dRSVP) protocol is proposed. dRSVP is an enhanced version of RSVP, aiming at providing dynamic quality-of-service (QoS) support in a variable bandwidth environment (e.g., wireless) through guarantees of ranges of bandwidth instead of specific values. Flow rejection occurs when the channel quality decreases to a level that even the minimum bandwidth requirements per flow cannot be fulfilled. The proposed algorithm aims at improving the flow dropping probability of dRSVP, without affecting the bandwidth utilization. Its operation is based on setting priority classes and rejecting the minimum required number of flows per class, in order to guarantee QoS to the remaining. Both mathematical analysis and simulation results show that the overall flow dropping probability can be significantly reduced.