Aims The extent that pre-diabetic fasting plasma glucose (FPG) levels influence the effectiveness of lifestyle interventions in preventing type 2 diabetes (T2DM) is uncertain. We aimed to determine if the outcome of lifestyle intervention in people with impaired glucose tolerance (IGT) differs in those with normal or impaired FPG levels. Materials and Methods Data were used from the Da Qing Diabetes Prevention Outcome Study, which was a 30-year follow-up of a 6-year randomized trial of lifestyle intervention in 576 people with IGT. We then conducted a post-hoc analysis to compare the efficacy of intervention to reduce the incidence of T2DM and its complications in those with baseline FPG Lifestyle intervention reduced the cumulative incidence of T2DM by 37%-46% in those with baseline FPG <100 mg/dL and by 47%-51% in those with FPG >= 100 mg/dL. The FPG <100 mg/dL group had a lower cumulative incidence of diabetes and 6.41 years median delay in its onset compared with 2.21 years delay in the FPG >= 100 mg/dL group. In those with FPG <100 mg/dL intervention was associated with at least as great a reduction in cardiovascular disease and all-cause mortality as in the FPG >= 100 mg/dL group. Conclusions Lifestyle intervention reduced the incidence of T2DM in people with IGT regardless of baseline FPG levels, and in those with FPG <100 mg/dL led to a substantial delay in its onset. All persons with IGT, with normal or impaired FPG levels, may benefit from lifestyle intervention to delay its onset and mitigate the incidence of T2DM.