Achieving uniform bolt preloads is an important and difficult issue, when bolting up a pipe flange connection with a number of bolts. Repeated bolt-up operations are, therefore, commonly conducted to get uniform bolt loads. In this study, an effective one-pass bolting up procedure to get uniform bolt loads is proposed by using finite element analysis with elastic interaction coefficient method being incorporated. Furthermore, multi-pass bolting up procedure is also examined to avoid high initial bolt clamping forces that might be generated in the one-pass tightening. These procedures are applied to class 300 lb 20 inch flanges with solid-metal flat gasket and compressed asbestos sheet gasket. The validity of the procedures is substantiated by conducting bolting up experiment using calculated initial clamping forces.