Background: Children in resource-limited countries are more likely to die from treatable conditions than those in higher resource settings due to a lack of the right essential medicine at the right time. Globally millions of children die every year from conditions that could be treatable with existing medicines before they reach their fifth birthday. This study aimed in assessing the availability and affordability of essential medicine for children in selected health facilities of southern nations, nationalities, and peoples’ regions (SNNPR), Ethiopia. Method: A medicine outlets-based cross-sectional study was conducted to assess the availability, affordability, and prices of the 30 selected EMs for children in 30 public and 30 private medicine outlets in SNNPR from March 29 to May 5, 2019, applying WHO and Health Action International (HAI) tools. Availability was expressed as the percentage of sampled medicine outlets per sector that the surveyed medicine was found on the day of data collection. The number of daily wages required for the lowest-paid government unskilled worker (LPGW) to buy one standard treatment of an acute condition or treatment for a chronic condition for a month was used to measure affordability and median price ratio for the price of EDs. Results: Availability was varied by sectors, type of medicines, and level of health facilities. The average availability of EMs was 57.67% in the public sector and 53.67% in private sectors. Ceftriaxone, ORS, zink sulfate, and cotrimoxazole were the most widely available medicine types in both sectors. The median price ratios (MPR) for lowest-priced (LP) medicines were 1.26 and 2.24 times higher than their international reference price (IRP) in the public and private sectors respectively. Eighty-two percent of LP medicines in the public and ninety-one percent of LP medicines in the private sectors used in the treatments of prevalent common conditions in the region were unaffordable as they cost a day’s or more wages for the LPGW.Conclusion: Availability, affordability, and price are determinant pre-requisite for EMs access. According to the current work, although fair availability was achieved, the observed high price affected affordability and hence access to EMs.