The fundamental mechanism for the generation of pipe wall vibration and subsequent external acoustic radiation from pipes due to internal flow disturbances is the coincidence of internal higher order acoustic modes with resonant bending modes in the pipe wall [1][2][3]. This mechanism gives rise to enhanced vibration response and external acoustic radiation compared with that for undisturbed flow in a straight pipe. A method is presented for reducing the vibration amplitudes of the coincident structural resonances, by using a coincidence damper. The damper consists of a metal ring attached to the pipe by several discrete rubber inserts. The theoretical model of the pipe with the attached damper is developed by using the receptance technique where the ring is modelled as a rigid mass and the rubber inserts are modelled by using a complex stiffness. By reducing the receptance of the structural modes in the region of the coincidence frequency, the enhanced structural response caused by coincidence matching is reduced. Experimental and theoretical results demonstrating the effectiveness of the coincidence damper at reducing selective structural resonant modes are presented. Reductions in structural quality factor (Q) levels of the order of 10-15dB have been consistently achieved at the appropriate resonance frequencies.