Four hundred and twenty-two consecutive hospitalized suicide attempts made by 15-19 year old girls and boys in Helsinki area were investigated. One hundred and twenty suicide attempts were made by 115 boys and 302 by 247 girls. Differences between sex were analyzed. Boys had more severe adaptive problems. Their overall level of functioning was poorer than was that of the girls. Their physical health was not as good as that of the girls. Boys did not carry out more severe suicide attempts as concerns the estimated lethality and intent of the attempt, but their suicide attempts seemed to be connected with more severe physical, mental and social problems. Boys were more susceptible to alcohol provoked suicidal behaviour than girls, and they presented less appealing motives. The outcome of the boys was much worse than the outcome of the girls. Risk ratio for suicide during the 5-year follow-up was 2.0 for boys and 0.55 for girls. Risk ratio concerning violent death was 2.43 for boys and 0.33 for girls. Young male adolescents attempting suicide should be taken very seriously as a risk group for subsequent suicide.