Objectives: A meta analysis of the literature on treatment approaches to malnutrition in cystic fibrosis (CF) was conducted to evaluate the effectiveness of oral supplementation, enteral nutrition, parenteral nutrition, and behavioral intervention on weight gain before and after treatment. Study design: Eighteen studies were reviewed: four behavioral, sir. supplement, five enteral nutrition, and three parenteral nutrition. Results: The weighted effect size for weight gain was large for each intervention: 1.51 behavioral, 1.62 oral, 1.78 enteral, and 2.20 parenteral intervention. All interventions produced a large effect for weight gain in patients with CF. A univariate analysis of variance indicated no significant difference among the four interventions, F(3, 17) = 0.87, p > 0.05. Effect size for calorie intake was also evaluated when data were available (N = 7 studies), yielding a sample size of three behavioral, two enteral, and two oral supplement studies. Analysis of variance indicated a significant effect for treatment, F(2,4) = 13.34, p < 0.05, with post hoc analysis indicating that the behavioral intervention had a greater effect size for calorie intake than oral supplement. Conclusions: All interventions were effective in producing weight gain in patients with CF. Behavioral intervention appeared to be as effective in improving weight gain in patients with CF as more invasive medical procedures. These findings support continued research on nutrition intervention with patients with CF including controlled clinical trials of the interventions and long-term follow-up on the impact of nutrition on disease progression.