Monitoring the disease status of the patients with nonˉHodgkin lymphoma (NHL) at the molecular level is of great significance in the accurate individualized management. The novel next generation sequencingˉbased methods enable the quantitative detection of circulating tumor DNA (ctDNA) in peripheral blood with great sensitivity, which can overcome the shortages of biopsies and imaging scans. As a new biomarker of NHL, ctDNA provides the opportunity for disease genotyping, prognosis evaluation, therapeutic response and recurrence monitoring, which may ultimately improve the prognosis of NHL patients.