Objectives. This study determined the effect of enriched foods and all-around physical exercise on bone and body composition in frail elderly persons. Methods. A 17-week randomized controlled intervention trial, following a 2x2 factorial design-(1) enriched foods, (2) exercise, (3) both, or (4) neither-was performed in 1413 frail elderly persons (aged 78.6+/-5.6 years). Foods were enriched with multiple micronutrients; exercises focused on skill training, including strength, endurance, coordination, and flexibility. Main outcome parameters were bone and body composition. Results. Exercise preserved lean mass (mean difference between exercisers and nonexercisers: 0.5 kg+/-1.2 kg; P<.02). Groups receiving enriched food had slightly increased bone mineral density (+0.4%), bone mass (+0.6%), and bone calcium (+0.6%) compared with groups receiving nonenriched foods, in whom small decreases of 0.1%, 0.2%, and 0.4% respectively, were found. Those groups differed in bone mineral density (0.006+/-0.020 g/cm(2); P=.08), total bone mass (19+/-g; P=.04), and bone calcium (8+/-21 g; P=.03). Conclusions. Foods containing a physiologic dose of micronutrients slightly increased bone density, mass, and calcium, whereas moderately intense exercise preserved lean body mass in frail elderly persons.