The purpose of this retrospective analysis was to evaluate the hematologic toxicity and clinical outcome of salvage chemotherapy following 90Y-CC49 radioimmunotherapy (RIT) in patients with non-small cell lung cancer (NSCLC). Sixteen patients from a total of 37 who were enrolled in a phase I trial of 90Y-CC49 monoclonal therapy were treated with post-RIT salvage chemotherapy at our institution. Five patients had received chest radiation therapy prior to RIT, and seven patients had prior chemotherapy. The majority of these patients were treated with doses of 90Y of ≥ 14 mCi/m2 (8-20 mCi/m2), and four of them received concurrent 96-hour taxol infusion. The maximum tolerated dose of this study was exceeded at 17 mCi/m2, and grade 4 thrombocytopenia/neutropenia were the dose-limiting toxicities. Twelve patients received one chemotherapy regimen as salvage therapy, and four patients had more than one regimen. Four patients (25%) experienced reversible grade 4 neutropenia, but no grade 4 thrombocytopenia was observed. Five patients had stable disease. The median survival from start of salvage therapy was 5.5 months. Our data suggest that therapy with RIT did not significantly affect survival of these patients. Taking into consideration the potential clinical relevance of integration of RIT with other treatment modalities, it is important to expand this clinical experience in order to support combined modality strategies.