Introduction: Satraplatin has been given in combination therapy for lung cancer to utilize its radio-sensitizing properties. The optimal dose of satra-platin given concurrently with radiation therapy for locally advanced non-small cell lung cancer (NSC-LC) has not been defined. This phase I trial attempts to identify a maximally tolerated dose (MTD) and dose limiting toxicity (DLT) for Satraplatin given con-currently with radiation for locally advanced N-SCLC. Patients and Methods: 15 patients with histologically confirmed Stage IIIA/B NSCLC entered onto this study with four dose escalations (10 to 40 mg daily) of Satraplatin. Eligibility included patients with NSCLC and one of the following criteria: 1) previously untreated, inoperable disease and planned to receive radiation therapy to primary disease site;2) previously resected disease with mediastinal relapse;or 3) metastatic disease in no more than one distant site. Results: The most common toxicities reported were all grades of fatigue (n = 9), nausea (n = 9), constipation (n = 7), fever (n = 7), and vomiting (n = 6). No DLT at the 1st, 2nd, and 3rd dose levels was identified. At the 4th dose level, one patient developed grade III elevation of liver function tests (LFTs) and a second patient developed grade III diarrhea with fever requiring hospitalization. There were 8 partial responses out of 11 evaluable patients for response (RR 67%). Conclusion: Elevated LFTs and diarrhea appear to be the principal DLTs of concurrent daily oral Satraplatin and thoracic radiation in the outpatient setting. The MTD of concurrent Satraplatin with thoracic radiation therapy appears to be 40 mg daily.