Risk management is a major concern in the building industry.Poor management of risk has resulted in delays and some cases litigation.Several strategies have been adopted for managing risk, Contingency Sum is one strategy.Study was to identify existing methods, factors, management and propose guidelines for determining and monitoring Contingency Sum. Random sampling was used for the sample size for professionals, using Kish formula.250 questionnaires were administered and 53.2% were returned.Data collected were analysed using the relative important index(4-most important factor and 1-least important ranking).Kendall's co-efficient of concordance was used to measure the degree of agreement among the professionals.Study identified percentage method as the most widely used.Unexpected ground conditions, design consideration and inflation were the influential factors.Contingency Sums were mainly monitored by Project Managers.Study concludes by proposing a method for determining contingency sum, suggests the use of a more scientific methods like Estimating Using Risk Analysis or the Monte Carlo Simulation. An over site body should set up to monitor the use of Contingency