Single-parent families maybe exposed of personal, interpersonal and family problems. Thus, the aim of the current research wasthe comparison of parental monitoring, affiliation with delinquent peers and high risk behaviors between single parent and two-parent adolescents. 100 single-parent adolescents and 100 two-parent adolescents in Eslamabad-e Gharb city of Kermanshah, Iran, were selected through Convenience sampling method, and responded to parental monitoring and affiliation with peers delinquent questionnaires and adolescent risk-taking scale. The results showed a significant difference between single parent and two-parent adolescent in terms of all three compared variables. Actually, single parent adolescents obtained lower score in parental monitoring and higher scores in affiliation with delinquent peers and high risk behaviors in comparison with two-parent adolescents. According to the results, it can be said that single-parent families are more exposed to problems. Therefore interventions to teach appropriate parenting style forparentsof single-parent adolescents and proper trainingsareessentialto prevent affiliation with delinquent peers and high risk behaviors among single-parent adolescents.Single-parent families maybe exposed of personal, interpersonal and family problems. Thus, the aim of the current research wasthe comparison of parental monitoring, affiliation with delinquent peers and high risk behaviors between single parent and two-parent adolescents. 100 single-parent adolescents and 100 two-parent adolescents in Eslamabad-e Gharb city of Kermanshah, Iran, were selected through Convenience sampling method, and responded to parental monitoring and affiliation with peers delinquent questionnaires and adolescent risk-taking scale. The results showed a significant difference between single parent and two-parent adolescent in terms of all three compared variables. Actually, single parent adolescents obtained lower score in parental monitoring and higher scores in affiliation with delinquent peers and high risk behaviors in comparison with two-parent adolescents. According to the results, it can be said that single-parent families are more exposed to problems. Therefore interventions to teach appropriate parenting style forparentsof single-parent adolescents and proper trainingsareessentialto prevent affiliation with delinquent peers and high risk behaviors among single-parent adolescents.