The purpose of this study is to examine the influence of peer groups and parents on adolescents' health. It was examined how communication relationships with peer groups and parents affect youngsters life satisfaction, sadness, irritability, being nervous, fear and troubles in falling asleep. The sample was comprised of individuals that participated in the study in continental Portugal, integrating the European study HBSC - Health Behavior in School - aged Children. The study was made during January 2006 and included a total of 4,877 students attending the 6th, 8th and 10th grades from Portuguese public schools, with an average age of 14 years of age. The instrument used was the HBSC questionnaire. The results showed that adolescents' health is influenced by their relationship with their parents and peers. When the communication with both is easy, youngsters are more satisfied with life and have less health negative symptoms. When compared with peers, parents influence positively the adolescents' health.