THE rotation rate of pulsars decreases as kinetic energy is lost by the emission of electromagnetic radiation and particles. This gradual spin-down is sometimes interrupted, however, by abrupt increases in rotational frequency. Such discontinuities-known as glitches-arise because of structural changes in neutron stars, and can provide valuable information on their interiors. Glitches generally occur more frequently in younger pulsars1. A timing program has been monitoring the periods of the forty predominantly young pulsars found in the Jodrell Bank 1,400-MHz survey2,3,4. As part of this study, we report here the observation that one pulsar, PSR1737-30, has undergone no fewer than five glitches in the past three years. Although not especially young, this pulsar is glitching at a rate nearly an order of magnitude greater than any other known pulsar. We speculate that the higher temperatures associated with the youngest pulsars might prevent the build-up of the stresses the sudden release of which is the cause of glitches. If so, this might explain the lower glitch activity now evident in those pulsars that are less than 2,000 years old.