Objective: to compare two instruments classically utilized by the literature and indicated to evaluate possible distortions of body image in adolescents and adults of both sexes. Method: the Body Shape Questionnaire (BSQ) and the Silhouette Figure Scale (SFS) was applied in 118 students, aged 16.5 ± 1.2 years, 62 boys and 56 girls of 4 public schools. The BSQ measures body shape concerns and the feeling of being "fat"; while the SFS evaluates the actual shape perception and the desirable shape, based on 15 silhouettes of each sex, presented in individual cards, with progressive variations, from the thinner (BMI = 12.5 Kg/m 2) to the larger (BMI = 47.5 Kg/m 2). Besides that, weight and height were measured for the Body Mass Index (BMI) calculation and posterior comparison with the SFS. The data were submitted to the statistical treatment consisted in a descriptive analysis, a Pearson's correlation test between the instruments and the Student's T-Test for comparison between the sexes. Results: The BSQ showed that 14.5% of the boys and 60.7% of the girls presented some level of body image distortion. The SFS on girls showed a "actual" BMI of 26.9 Kg/m 2 while the real BMI were 21.5 Kg/m 2. The EFS on boys showed a "actual" BMI of 23.7 Kg/m 2 , while the real BMI were 21.0 Kg/m 2 , indicating a prevalence of body image distortion in both sexes. The statistical analysis showed a significant positive correlation (r=0.8) between the two instruments, however, the SFS did not presented differences between the sexes (p=0.93), while the BSQ detected a higher level of distortion by the girls [F(1,110)=13.80; p<0.001)]. Conclusion: the body image distortion was detected by both instruments, however, the BSQ detected differences due to sex, while SFS appears not sufficiently sensible to detect sex differences in adolescents.