Background/objectives: To examine whether higher fasting plasma glucose (FPG) levels were independently associated with left ventricular (LV) mass and/or geometry in elderly, otherwise healthy subjects. Methods: We tested cross-sectional associations between echocardiographically determined LV mass/geometric patterns, cardiovascular risk factors, and FPG categorized as normal fasting glucose (NFG), impaired fasting glucose (IFG), and untreated diabetes mellitus (DM), in 486 men and 207 women aged 56-79. years without overt cardiovascular disease, who received no cardiovascular, anti-diabetic, or lipid-lowering drugs and had a preserved LV ejection fraction >. 50%. Results: Unadjusted mean LV mass index (LVMI) was significantly greater among subjects with DM than those without (90+/-26g/m2 vs. 85+/-20g/m2, p=0.01), as were both relative wall thickness (RWT) (0.43+/-0.09 vs. 0.40+/-0.08, p=0.01) and prevalence of concentric LV hypertrophy (LVH) (11% vs. 6%, p=0.03). However, only RWT remained significantly associated with the presence of DM after multivariable adjustment (p=0.04). Interaction analyses revealed that greater LVMI/LVH was predominantly associated with higher levels of N-terminal pro-brain natriuretic peptide (NT-proBNP) among subjects with IFG or DM, but not NFG. Conclusions: Subjects with untreated DM had higher values of LVMI and a greater prevalence of concentric LVH, but the associations were not independent of other risk factors. NT-proBNP was primarily associated with greater LV size in subjects with IFG or DM.