ABSTRACT. This research presents single-vendor multi-buyers model with unstablelead time and setup cost and transportation in divergent supply chain. The vendor’sconcern is on crashing of the setup cost, and buyers is on reducing lead time. Thevendor manufactures products and delivers them to the buyers located in differentlocations by a fleet of vehicles with identical capacity. The lead time demand isnormally distributed. Excluding transportation time, the lead time component ofbuyers can be reduced by adding crashing cost. Lead time demand per unit time onbuyers are normally distributed. The purpose of this research is to formulate anintegrated single-vendor multi-buyers model to determined  the optimal solution oforder quantity, safety factor, lead time, shipment frequency and routing decisionwhich has been illustrated through a numerical example.Keyword: integrated inventory model, unstable lead time, unstable setup cost,  service level constraint, partial backorder