AbstractThis article deals with an inventory problem where the supply is available only during an interval of (random) lengthX. The unavailability of supply lasts for a random durationY. Using concepts from renewal theory, we construct an objective function (average cost/time) in terms of the order‐quantity decision variableQ. We develop the individual cost components as order, holding, and shortage costs after introducing two important random variables. Due to the complexity of the objective function whenXandYare general random variables, we discuss two special cases and provide numerical examples with sensitivity analysis on the cost and noncost parameters. The article concludes with a discussion of the comparison of the current model with random yield and random lead‐time models. Suggestions for further research are also provi