The purpose of this study was to evaluate the initial body compositional changes experienced by malnourished patients requiring home parenteral nutrition (HPN) for repletion. Eight patients were prospectively studied for 3 months. Body composition was determined by dual-energy X-ray absorptiometry (DXA), and a comprehensive nutrition assessment was performed including body weight, visceral proteins, triceps skinfold (TSF), midupper arm circumference (MUAC), midupper arm muscle circumference (MUAMC), body mass index (BMI), delayed hypersensitivity skin tests (DHST), and diet history. Body composition measured by DXA showed an increase in (mean +/- SD) total fat from 5770 +/- 2805 to 10581 +/- 1980 g (p < .001) and bone mineral content from 2155 +/- 429 to 2190 +/- 443 g (p = .047). Lean soft tissue remained unchanged. Body weight and BMI increased from 47.7 +/- 6.6 to 53.6 +/- 8.2 kg (p = .006) and from 16.6 +/- 1.5 to 18.6 +/- 1.5 kg/m2 (p = .005), respectively. TSF increased from 6.3 +/- 3.1 to 10.4 +/- 4.0 mm (p < .001), and MUAMC remained stable. There was a significant improvement in transferrin from 191 +/- 82 to 326 +/- 128 mg/dL (p = .043), and a trend toward improvement in albumin and DHST. Body weight was highly correlated with DXA weight at baseline (r = .997; 95% confidence interval [CI], 0.98 to 1.00; p < .001) and at 3 months (r = .988; 95% CI, 0.93 to 1.00; p <.001). TSF correlated with total fat as measured by DXA at baseline (r = .839; 95% CI, 0.33 to 0.97; p = .009) but not at 3 months (r = .693; 95% CI, -0.02 to 0.94; p = .057). MUAMC correlated with lean soft tissue measured by DXA both at baseline (r = .739; 95% CI 0.07 to 0.95; p = .036) and at 3 months (r = .870; 95% CI, 0.43 to 0.98; p = .005). Physical activity, on a subjective scale of 1 (low activity) to 3 (high activity), improved over the 3-month period from 1.3 +/- 0.5 to 2.2 +/- 0.8 (p = .031). Initial weight gain experienced by malnourished HPN patients is primarily fat. Bone mineral content increases, but lean soft tissue does not change. Overall nutritional status is improved as exhibited by significant improvements in body weight and serum transferrin and a trend toward improvement in albumin and delayed hypersensitivity skin tests.