Rotary root canal instruments manufactured from nickel-titanium alloy have proved to be a valuable adjunct for root canal therapy. Over the past two decades, instrument design has been considerably modified; progress has been made in manufacturing, as well as alloy processing. Clinical procedures and ideal working parameters are still being refined as new instruments continue to be introduced to the market. This review is intended to summarize clinical and laboratory findings for several current instruments. Some guidelines and usage parameters are also detailed. Keywords: nickel-titanium, root canal anatomy, root canal preparation, shaping