This paper deals with multiple criteria decision making problem with incomplete information when multiple decision makers (Multiple Criteria Group Decision Making: MCGDM) are involved. Usually decision makers (DMs) are willing or able to provide only incomplete information, because of time pressure, lack of knowledge or data, and their limited expertise related with problem domain. There have been just a few studies considering incomplete information in group settings. This incompletely specified information constructs region of linear constraints and therefore, pairwise dominance relationship between alternatives reduces to intractable nonlinear programmings. Hence, to handle this difficulty, we suggest a method, utilizing individual decision results to form group consensus. Final group consensus ranking toward more agreement of participants can be built through solving a series of linear programmings, using individual decision results under group members' possibly different weight constraints. (C) 1999 Elsevier Science B.V. All rights reserved.