BACKGROUND OF THE STUDYIt is believed that one of the prevailing problems of construction industry in Nigeria is the impact of delays in project delivery. It is very important for both public and private projects to be completed on time and within budgets. Normally, achieving the projects within predetermined time, budget and quality is the basic purpose of construction project control. Construction delays is simply the time during which some part of the construction project has been extended beyond what was originally planned due to unanticipated circumstances.Project success is basically to gain the project objectives that are classically defined by the need to complete a project on time, within the budget and with appropriate quality. Hence any disruptions to the project objectives will certainly contribute to project delays with the specified adverse effect on project objectives. Delays can give rise to disruption of work and loss of productivity, late completion of project, increase time related costs, third party claims, abandonment or determination of contract. Delays are costly and often result in disputes and claims. Furthermore, delays effects the feasibility for project owner and retard the development in construction industryBefore determining the effect of delay on project, one must determine whether the delay is critical. Additionally, all delays are either excusable or non-excusable. Both excusable and non-excusable can be defined as either concurrent or non-concurrent.