Abstract
The occurrence of overrun in cost and time in a project that is usually caused by contractors, will generally make peopleput the blameonthem. This happensas a result of the lack of knowledge possessed by the contractors in determining the solution to be undertakendue totheir mistakes, especially when it comes to tendering process as what had happened in the cases that were reported in Supreme Court of Canada. This paper aims to identify the types of mistakes, factors that contribute to the mistakes and the responsiveness to the mistakes so that the contractor will be able to manage and control the mistakes, as well as the solution, along with preventing them from happening, and in making decision whether or notthey may withdraw from the bidding when the fault has been discovered or whether they should request for leniency from the client for a second chance in re-submitting the bid after the discovered inaccuracy. This research has been done based on cases that were related to the contractor's mistakes during tendering which were collected from the Supreme Courts of Canada. The data have been analysed and interpreted by legal methodology, in which the result shows that the ability level of the contractors to respond to the mistake is unsatisfactory, and the fault is continuouslybeingmade. The findings are expected to educate and provide awareness to the contractors relating to the matters discussed.