Aim: To investigate the usefulness of IGF-1, IGFBP3 (BP1) and IGFBP1 (BP3) as biochemical indicators to monitor nutritional status and response to Megestrol acetate (MA) Study type: Randomized, double-blind, placebo-control trial. Subjects: 27 children, age±SD; 13.89±2.69, affected of solid tumors, anorexia and weight loss. Interventions: Subjects were randomly divided into the treated group (TG) (n=15) and control group (CG) (n=12) which then received MA(5 mg/kg/day) or placebo, respectively, for 30 days. Measurements: Nutritional status was assessed by anthropometrical parameters, appetite by a categorical scale and quality of life by the Children's Play Lansky scale. IGF-I, BP1 and BP3 were measured by IRMA (DSL®). Data was determined before and after 30 days of MA treatment. Results: Statistical analysis was done using Paired t-tests and Wilcoxon's signed rank and Mann-Whitney U test In the TG, all the anthropometrical measurements, appetite and quality of life improved significantly (p<0.01) after one month of treatment. IGF-1 and BP3 increases (p<0.01). In the CG there was a significant decrease (p<0.01) in the subscapular skinfold, weight, body mass index, appetite, and quality of life. There were significant differences (p<0.01) between the CG and TG with respect to all the variables studied, except for IGBP1 (p=0.05). There was a significant correlation between weight change and BP3 (p<0.05, r=0.5, Pearson's correlation coefficient). Conclusion: MA is a powerful appetite stimulant, with subjective and objective effects on the nutritional status of children with cancer anorexia and weight loss. We propose the use of IGF-1 and BP3 as biochemical indicators to monitor nutritional status and MA response in children with cancer treated with MA.