An innovative method, namely, level maintain method, is proposed for finding all efficient solutions to a bottleneck-rough cost interval integer transportation problem in which the unit transportation cost, supply, and demand parameters are rough interval integers and the transportation time parameter is an interval integer. The solving procedure of the suggested method is expressed and explained with a numerical example. The level maintain method will dispense the necessary determined support to decision-makers when they are handling time-related logistic problems in rough nature. © 2018, Springer Nature Switzerland AG.