With the purpose of designing an instrument to measure self-care capacity in adolescents suffering from diabetes mellitus, a descriptive cross-sectional study was carried out in the context of the "José Luis Miranda" Pediatric Hospital in Santa Clara, Villa Clara, Cuba. The population consisted of all the adolescents who suffered from diabetes mellitus in that period (90), by non-probabilistic intentional sampling of voluntary subjects, 40 were worked with. The main variables of the study were: age group, sex, skin color, origin, parents' schooling, physical exercises, attitude towards the disease, complications and continuous relationship with the health center. The main results were: 45% represented the 10-12 years age group, 80% of the patients had white skin color, 75% did not do physical exercise.