This was a randomized, double-blind, double dummy, multicenter study to assess the safety, efficacy and tolerability of the addition of RSG (rosiglitazone) to sub-maximal MET (metformin) combination relative to maximal MET monotherapy in subjects with type 2 DM (diabetes mellitus). The total duration of the study was approximately 20 months. The study consisted of a two-week washout period, a four to seven-week MET titration period, and a 24-week randomized treatment phase in which subjects, stratified by prior therapy, received either RSG + MET combination therapy or MET monotherapy.