Objective: To estimate the prevalence of contraceptives use among female adolescents and to describe their demographic and socioeconomic characteristics.Methods: Cross-sectional study carried out at the Community Management District "Restinga/Extremo Sul", in Porto Alegre, Southern Brazil, from July to December 2009. The sample included 487 adolescents aged ten to 19 years old, who live in this community. The main outcome was the use of contraceptive method alone or in association whit other methods; independent variables were age, skin color, social class, marital status, education level in years, marital situation, job, religion, unplanned pregnancy and abortion.Results: Among the interviewed adolescents, 51% had 15-19 years old, 67% were white, 29% and 59% respectively belonged to A/B and C socio-economical levels. The first sexual intercourse occurred on average at 15 years old. The use of contraceptive methods was reported by 75% of sexually active teens. The pill was the most frequently mentioned method (62%), followed by condoms (38%) and non-oral hormonal contraceptives (injectable or implant, 16%). No significant association was found between the use of any contraceptive method and demographic and socioeconomic variables.Conclusions: The number of sexually active teenagers who do not use effective contraception (25%) is alarming. Resultados: Das adolescentes entrevistadas, 51% tinham entre 15 e 19 anos, 67% eram brancas, 29% pertenciam às classes A e B e 59%, à classe C. A sexarca ocorreu, em média, aos 15 anos. O uso de algum método contraceptivo foi referido por 75% das adolescentes sexualmente ativas. A pílula foi o método mais referido (62%), seguido do preservativo masculino (38%) e do anticoncepcional hormonal não oral (injetável ou implante, 16%). Não houve associação significante entre o uso de método contraceptivo e as variáveis demográficas e socioeconômicas analisadas.Conclusões: O número de adolescentes sexualmente ativas sem uso de contracepção eficaz (25%) é preocupante.Palavras-chave: anticoncepção; adolescente; escolaridade. RESUMENObjetivo: Estimar la prevalencia de uso de métodos contraceptivos entre las adolescentes del sexo femenino y describir las características demográficas y socioeconómicas.Métodos: Estudio transversal realizado en la Comunidad Gerencia Distrital Restinga/Extremo Sur, Porto Alegre, RS, Brasil, de julio a diciembre de 2009. Se entrevistó a 487 adolescentes de 10 a 19 años, que viven en esa comunidad. El desenlace en estudio fue el uso de método contraceptivo utilizado aisladamente o en asociación con otro método, las variables independientes fueron: edad, color de la piel, clase social, estado civil, escolaridad en años de estudio, situación conyugal, actividad remunerada, religión, embarazo no planeado y aborto.Resultados: De las adolescentes entrevistadas, el 51% tenía entre 15 y 19, el 67% eran blancas, el 29% pertenecían a las clases A y B y el 59% a la clase C. La primera relación sexual ocurrió, en promedio, a los 15 años. El uso de algún método con...