There is no data on safety and efficacy of a second course of ibritumomab tiuxetan. In this work, data on patients with B-cell NHL who were treated with two courses of ibritumomab tiuxetan were analyzed. Eighteen such patients were analyzed (age: 58 years, 48-91), with a median of four prior regimens (1-7), stem cell transplantation (n = 5), and radiation therapy (n = 6). After the first course, G3/4 neutropenia and thrombocytopenia was 35% and 41%; overall response rate (ORR) was 89%; time between courses was 16.6 months (6.0-42.7). After the second course, the incidence of G3/4 neutropenia and thrombocytopenia was 28% and 44%; and ORR 77%. There were no infectious or bleeding complications, secondary myelodysplastic syndromes, or leukemias. Retreatment with the ibritumomab tiuxetan regimen was well tolerated, with a safety profile similar to that of the first course. To conclude, patients who benefited from the first course of ibritumomab tiuxetan can benefit from retreatment.