This paper aims to determine the reorder level when the lead time demand has the Marshall–Olkin extended Weibull distribution which is introduced by Marshall and Olkin in 1997. Using some methods of estimations such as maximum likelihood, method of moments, percentile based estimation and least squares the three unknown parameters of the distribution are estimated. Using the value of and the estimated parameters according to each method the most important functions in inventory models such as the protection lost sales (i.e., the probability of not going out of stock) and the potential lost sales (i.e., the unsatisfied demand) were obtained. Finally some conclusions are presented.