INTRODUCTIONThis study is to identify the major causes of delay and time overrun in project execution. Delay is one of the biggest problems often experienced on construction project sites. Delays can cause negative effects such as increase d costs, loss of productivity and revenue, lawsuitsbetween owners and contractors and could result to contract termination. From literature survey, more than thirty causes were identifiedProject execution is burdened with a lot of challenges, among which is delay and time overrun.It has been researched, that delay is a major setback in the construction industry. The problem of delays in the construction industry is a global phenomenon. Odeyinka and Yusuf (1997) observed that the performance of the construction industry in Nigeria in terms of time was poor.In construction term delay refers to something happening at a later time than planned, expected and specified in the contract or beyond the date agreed upon for the delivery of the project (pickavance 2005). While time overrun is as a result of delay when the duration of the project is extended, it result to time overrun.Some of the identified causes of delay in construction projects include;Some of the identified causes of time overrun in projects execution include;Odeyinka and Yusif (1997) affirmed that poor site supervision, weather conditions and conflicts were major causes of time overrun. Time is factor that is very essential in all activities that has to be carried out, in the contract document a specific time phase is given for delivery of project and if the time is being exceeded more money is often spent. Also delay can lead to reduced profit for builder and abandonment of building project by the client.