Background: HIV is the strongest risk factor for developing tuberculosis (TB) among people with latent or new Mycobacterium tuberculosis infection. Isoniazid preventive therapy (IPT) reduces the risk of active TB among people living with HIV by up to 62%. Despite evidence that IPT is safe and efficacious, its provision remains low globally. The current study aimed at documenting IPT uptake, adherence, and completion rates, as well as the correlates of IPT uptake among HIV-infected children in Kenya. The study also assessed the knowledge, attitude, and practices of health-care workers (HCWs) with regard to IPT. Methods: A health facility-based cross-sectional study was conducted. Data were collected from caregivers of HIV-infected children as well as HCWs using an interviewer-administered questionnaire. Logistic regression was used to determine the factors associated with IPT uptake. Results: The study enrolled 111 child-caregiver dyads. Most of the caregivers were female (n=75, 77.3%) and HIV-positive (n=82, 85.4%). The majority of children were male (n=65, 58.6%) and on ART (n=106, 95.5%). Overall, 59 children were on IPT (uptake of 53.2%, 95% confidence interval [CI], 43.9% to 62.4%). Out of the 25 children who had been on IPT for more than 6 months, 22 (88.0%) successfully completed the 6-month course of treatment. Further, 27 of the 34 children (78.4%) who were on IPT at the time of the study demonstrated satisfactory adherence to the therapy (no doses missed). The caregivers’ attributes that were associated with IPT uptake included having a secondary school education (adjusted odds ratio [aOR] 0.13; 95% CI, 0.03 to 0.67) and having been on IPT (aOR 27.50; 95% CI, 5.39 to 140.28). The characteristics of children that were significantly associated with IPT uptake were higher median baseline CD4 count (P=.007) and higher median current CD4 count (P=.024). Conclusion: The study demonstrated suboptimal IPT uptake but favourable adherence and treatment completion rates. There was almost universal awareness of IPT within the study sample. Furthermore, the majority of the HCWs had a favourable attitude towards IPT. However, the attendant IPT practices were inadequate, with majority of HCWs reporting that they had never initiated IPT, prescribed IPT within the last 12 months, or renewed an isoniazid prescription.