Background Assessement of the pattern of admission and treatment outcomes of critically ill pediatrics admitted to pediatric intensive care units (PICU) in developing countries is crucial. In these countries with resource limitations, it may help to identify priorities for resource mobilization that may improve patient service quality. The PICU mortality rate varies globally, depending on the facilities of the intensive care unit, availability of experties, and admission patterns. This study assessed the admission pattern, treatment outcomes, and associated factors for children admitted to the PICU. Methods A retrospective cross-sectional study was implemented on 406 randomly selected pediatrics patients admitted to the PICU of Tikur Anbessa Specialized Hospital from 1-Oct-2018 to 30-Sept-2020. The data were collected with a pretested questionnaire. A normality curve was used to check for data the distribution. Both bivariable and multivariable analyses were used to see association of variables. A variable with a p-value of < 0.2 in the bivariable model was a candidate for multivariate analysis. The strength of association was shown by an adjusted odds ratio (AOR) with a 95% Confidence interval (CI), and a p-value of < 0.05 was considered statistically significant. Frequency, percentage,and tables were used to present the data. Results A total of 361 (89% response rate) patient charts were studied, 197 (54.6%) were male, and 164(45.4%) were female. The most common pattern for admission was a septic shock (27.14%), whereas the least common pattern was Asthma 9(2.50%). The mortality rate at the pediatric intensive care unit was 43.8%. Moreover, mechanical ventilation need (AOR = 11.2, 95%CI (4.3–28.9), P < 0.001), need for inotropic agents (AOR = 10.7, 95%CI (4.1–27.8), P < 0.001), comorbidity (AOR =8.4, 95%CI (3.5–20.5), P < 0.001), length of PICU stay from 2 to 7 days (AOR = 7.3, 95%CI (1.7–30.6), P = 0.007) and severe GCS (< 8) (AOR = 10.5, 95%CI (3.8–29.1), P < 0.001) were independent clinical outcome predictors (mortality). Conclusion The mortality rate at the PICU was 43.8%. Septic shock, and meningitis were the common cause of death and the largest death has happened in less than 7 days of admission.