Rejecting a takeoff at high speed in an airliner is a risky manoeuvre, however, if the decision is not made in a timely manner, at high speeds there is the strong possibility of overrunning the runway. The response times to reject a takeoff were measured in a flight simulator at a variety of speeds using 16 professional pilots. It was observed that as speed on the runway increased, response times decreased, up until a point just before V1 (the 'go/no-go' decision speed). At this point response times increased dramatically. The results are discussed within the context of the current aircraft certification parameters. Suggestions for further research are made, particularly with respect to extending this work to examine whole crew response times when rejecting a takeoff.