Back ground: Ensuring good adherence is critical to the success of highly active anti-retroviral therapy (HAART). Failure to adhere very closely to the regimens results in continued viral replication, treatment failure and the emergence of drug resistant strains of human immune deficiency virus (HIV). Although parents and caregivers may have primary responsibility for their children's medication-taking, there is no single study that examined parents influence on pediatrics highly active anti-retroviral therapy (HAART) adherence in our set up. The result of the study is expected to help device intervention strategies to improving children’s adherence on highly active anti-retroviral therapy (HAART). Objectives: To assess the status, determinants of adherence and identify parental factors influencing pediatrics highly active anti retroviral therapy (HAART) adherence in Addis Ababa. Methods: An observational: descriptive, cross sectional study was conducted in 9 Health institutions: public, private and Non Governmental Organizations (NGOs) in Addis Ababa. Multi-stage sampling procedure was used to select a total of 586 children: age 0 - 14 years, Human Immune Deficiency Virus (HIV) infected and started anti-retroviral therapy (ART) 12 weeks ago. Primary care givers of the children were enrolled after the nature of the study was explained that allowed informed decision to be made and written consent obtained. Data was collected from February 8- May 10, 2010 on socio demographic, parent factors, clinical markers, care givers to provider relationship and regimen variables. Structured questionnaire and focus group discussion were used. Univariate, bivariate and multivariate analysis was carried out. Result: The parental factors were strongly associated with non adherence; children who had non biological parents [OR=9.805(95%CI= 2.198, 43.736)], parents who didn’t communicate about HIV and ART adherence to their children [OR=3.915 (95%CI= 1.273, 12.036)], and parents who hadn’t good relationship with health care providers [OR=29.592(95%CI= 1.326, 660.333)] were more likely non adherent. Children who had more than four siblings [OR= 5.676 (95% CI=2.100, 15.339)] were also significantly associated with non adherence Conclusion: The parental factors were strongly associated with non adherence. The need for providers to have smooth relation ship with the care givers of the HIV infected children on antiretroviral therapy, support caregivers to communicate with their children about the disease and antiretroviral therapy adherence is critical. Further research is recommended to explore the validation of self report adherence using longitudinal study designs.