BACKGROUND:One of the treatments for leukaemia is chemotherapy. Side effects and toxicity of this treatment can be seen on the skin, adnexal, and mucous membranes. They might increase potential hydrogen (pH) value on the skin surface, therefore, disrupting epidermal barrier defences.AIM:To describe the pH of the skin in children with leukaemia who received chemotherapy.SUBJECT AND METHOD:This study was an observational descriptive, cross-sectional study, conducted from March until December 2016 with 32 children with leukaemia who treated at Haji Adam Malik General Hospital, Medan as subjects. Skin pH was measured by a pH meter.RESULT:We found mean skin pH in ALL (6.28 ± 0.58), CML (5.9 ± 0) and AML (6.5 ± 0.50). The mean skin pH after 1-5 weeks of chemotherapy was 6.13 ± 0.49, at 6-10 weeks (6.32 ± 0.51), and at 11-15 weeks (7.12 ± 0.36). The mean skin pH of patients with two drugs (5.98 ± 0.44), four drugs (6.28 ± 0.55), and six drugs (6.63 ± 0.56).CONCLUSION:The highest mean of skin pH were obtained in AML group, 11-15 weeks length of chemotherapy and group with six drugs regimen.