SARS-COV-2 infection can be asymptomatic or mildly symptomatic. The effect of chemotherapy on an asymptomatic infected patient is unknown. Three hundred-thirty-four and 56 NFS were performed as screening for SARS-CoV-2 infection in 247 and 34 pediatric patients undergoing chemotherapy and stem cell transplantation, respectively. NFS was positive in 10 patients. All positive patients withdrew from chemotherapy. Nine patients became negative. One patient is still positive after 38 days.The identification of asymptomatic SARS-COV-2 infection is important to reduce the hospital spread of infection. Further studies are needed to define the least risky management of chemotherapy in asymptomatic SARS-CoV-2 patients.