The milk-run is an in-plant lean logistics application where from a central warehouse; full-boxes of components are supplied to the line-side buffer stock areas of the assembly stations, on a just-in time basis, and in a cyclic manner, so that the stations do not run out of stock . The associated problem is the cyclic Inventory Routing Problem (IRP). In this study, a two stage approach is proposed where a mixed-integer mathematical model is solved to assign the stations to the routes and to decide the service periods of the routes. At the second stage, travelling salesman problem needs to be solved to find the sequence at each route. In addition, an alternative mixed-integer mathematical model is developed where routes are constructed such that the sequence of stations and the service periods are determined for each route, simultaneously. Both of the models are assignment-based that considerably reduces the solution times of the IRP. A medium-size hypothetical data set was solved by the two approaches. According to the results, the proposed two-stage approach was found to perform better than the alternative assignment-based model, in terms of computation time.