OBJECTIVES: Incidental isolated mild to moderate thrombocytopenia is a frequent laboratory finding prompting a referral to pediatric hematology-oncology. We tested the hypothesis that patients with isolated asymptomatic mild thrombocytopenia would not progress to require an intervention from a pediatric hematologist-oncologist. METHODS: This is a 5-year retrospective review of 113 patients referred to pediatric hematology-oncology for isolated thrombocytopenia. Initial, lowest, and current platelet counts along with clinical course and need for interventions were recorded. Thrombocytopenia was categorized as mild (platelet count: 101-140 × 103/μL), moderate (platelet count: 51-100 × 10 3 /μL), severe (platelet count: 21-50 × 10 3 /μL), and very severe (platelet count: ≤20 × 10 3 /μL). RESULTS: Eight of 48 patients (17%) referred for initial mild isolated thrombocytopenia progressed to moderate thrombocytopenia at 1 visit. At present, 2 of these patients have moderate thrombocytopenia, 17 remain with mild thrombocytopenia, and 29 patients have resolved thrombocytopenia. Nine of 65 patients (14%) referred for moderate thrombocytopenia progressed to severe or very severe thrombocytopenia on 1 occasion. At present, no patients have severe thrombocytopenia, 18 remain with moderate thrombocytopenia, 14 improved to mild thrombocytopenia, and 33 have resolved thrombocytopenia. Only 3 patients required interventions from a hematologist, whereas 10 patients required therapy from other subspecialties. CONCLUSIONS: We only identified 3 patients (3%) with mild to moderate thrombocytopenia who required an intervention from a hematologist to improve platelet counts. Patients with isolated mild thrombocytopenia with a normal bleeding history and physical examination findings frequently have normalized their platelet counts within 1 month.