Queuing theory or waiting line models are basically a mathematical approach applied to theanalysis of waiting lines. Most queuing models applications are centered on the question of findingthe ideal level of services, waiting times and queue lengths. When an organization retain an excellentcustomer service. The customers are kept happy or satisfaction but for the an organization becomeexpensive. Most managers recognize the trade – off that must take place between the cost ofproviding good service and the cost of customer waiting time. The objective of this study is tomeasure the cost for three single channel waiting line models. The aim of this study is to comparebetween three single channel waiting line models. The cost for the three single channel waiting linemodels is calculated with different distributions. The study results showed that the cost whichcalculated for the (M/D/1) model is less than the other two models when the same data are used.Second the results showed that the cost which calculated for the (M/G/1) model when the servicerate (μ) is followed weibull distribution is less than the same model when the service rate (μ) isfollowed exponential and gamma distributions.