In the last decade, the maintenance and operation environment within Saudi Arabia went through many changes. These changes have been caused by different factors including: the decline of oil incomes, delays in monthly payments, and the cancellation of governemnt loans given to contractors. These factors had a great impact on the willingness of contractors to bid for the maintenance and operation projects. The study examines the bidding nature of maintenance and opeation projects in Saudi Arabia. It also demonstrates the general distribution of number of bidders according to the type and sizes of maintenance and operation projects. It will determine the most attractive type and size among those projects. Data was collected from government sectors reprewsenting all the regions of the Kingdom. Two mwthods of data analysis were used: the summary statistics analyses that illustrate the central tendency and dispersin of data, and special statistics testing methods through which means differences of individual group of data can be examined. The analysis shows that, the average number of bidders fluctutes and significantly different according to the type and size of pojects. The average number of bidders was found to increase as the project size increases. By presenting such issues, both clients and contractors knowledge of bidding characteristics are improved. Decline or fluctuation in number of bidders should have negative impacts on the long run whether on the bidding prices or on giving a chance to more unqualified contractors to engage into maintenance and operation enterprise