ObjecƟ ve: Determine the risk factors associated to adverse perinatal outcomes in pregnant teen populaƟ on. Barranquilla, January 2012-April 2013. Materials and Methods: Case-control study in women under 21 who received obstetric care in Hospital Simon Bolivar of Barranquilla during january 2012 to april 2013. Cases: 50 teens under 21 years old that showed adverse perinatal outcomes (low birth weight, preterm birth, small for gestaƟ onal age, toxemia, perinatal death and maternal death). Controls: 50 paƟ ents under 21 years old who received obstetric care and no adverse perinatal outcomes. Data were systemaƟ zed using Epi-Info 3.5.1; staƟ sƟ cal parameters were evaluated such as averages, p value, odds raƟ o, confi dence intervals a confi dence index of 95% was used. Results: For high school and lower educaƟ on level were obtained: OR = 3.16, CI = 1.03 - 9.68, p = 0.03; age of fi rst sexual intercourse ≤ 15 years showed OR = 22.3, CI = 6.8 - 72.4, p <0.00001; for unwanted pregnancy the results were: OR = 6.29, CI = 2.52 - 15.6, p <0.00001; meanwhile unsaƟ sfactory prenatal control showed: OR = 2.45, CI = 1.09 - 5.49, p = 0.02; family dysfuncƟ on showed: OR = 2.48, CI = 1.05 - 5.85, p = 0.03. Conclusion: The risk factors found were: fi rst intercourse at age 15 or earlier, unwanted pregnancy, prenatal unsaƟ sfactory and dysfuncƟ onal families