The degree of religiousness and religious observance have been studied as protective elements for various health behaviors. The present study assesses the relation between the degree of religiousness and the use of chemical substances and the presence of aggressive risk behaviors towards oneself or others, in a randomly selected sample of 252 schooled adolescents from the Metropolitan Region of Santiago, Chile. An ECRA-2 questionnaire was used, and the subgroups self-rated as very religious (n=57) and as not religious at all (n=50) were compared. The total group mean age was 17,7 years (SD 1,54), and 55,9% were female. As for religious ascription, 72,8% identified themselves as Catholics, 10,9% as Protestants , 4,7% as other religion and 11,7% as without religion. Twenty-two point six percent (22,6%) rated themselves as very religious, and 19,8% as not religious at all. The present comparison contrasts the subgroups self-rated as very religious (n=57) and as not religious at all (n=50). Of the very religious adolescents, 12,5% consumed marijuana more frequently than once per month, as compared to 41,7% of those who considered themselves as not religious at all (8,643; 2gl; p=0,013). The very religious adolescents felt sad and nervous more commonly than the not religious at all (22,7% vs 12,5% ; Χ2=5,175;2 gl; p=0,075); they reported a lower frequency of beating others (p=0,05), a lesser degree of participation in group fights (p=0,03), a lower frequency of shoplifting (p=0,08) and of cheating behaviors (p=0,002). The results of the assessment of the relationship between religiousness and self-destructive behaviors [univariate analysis of variance, F of 3,326 and R2 of 0,027 (p=0,0001)] point out that very religious adolescents have less tendency to self destruct. The conclusions of the present analysis are in accordance with the hypothesis of the protective role of religious observance. Further studies exploring deeper the spirituality, religiousness and observance endpoints as protective behaviors for mental or general health are recommended.