Introduction. Viral suppression rates among children and young adolescents living with HIV (CYALHIV) has been reported to be lower compared to adults. Follow up through viral load monitoring may influence their health outcomes. Objective. In this cross-sectional study we determined viral load monitoring practices and correlates of viral non-suppression of all CYALHIV in the main public hospitals in Kiambu County, Kenya. Data was abstracted from electronic medical records. Methods. Multivariable log binomial regression was used to estimate prevalence ratios (PR) and assess correlates of viral non-suppression. Adherence to viral load testing guidelines was also assessed. Viral non-suppression was defined as a viral load (VL) >1000c/ml. Results. Of the 252 CYALHIV, the median age was 11 (IQR: 7-13) years. At the most current VL, 14% were non-suppressed. Correlates of non-suppression included a history of Tuberculosis, [aPR = 4.25; 95% CI = 1.41-12.8; p = .01], antiretroviral drug side effects [aPR = 3.01; 95% CI = 1.37-6.62; p = 0.006] and having received enhanced adherence counselling (EAC) [aPR = 5.32; 95% CI = 2.00- 14.15; p = .001]. Although the timing of baseline VL tests improved over the years, routine VL monitoring as per the guidelines remained suboptimal. Conclusions. There is need for adherence to VL monitoring guidelines for prompt action among non-suppressed children.