Para-toluenesulfonamide (PTS), active ingredient being PTS, is a new anticancer drug applied through local intratumoral injection. The aim of this phase II clinical trial was to investigate the response and toxicity of standard gemcitabine (GEM) plus cisplatin (CIS) chemotherapy with concurrent intratumoral injection of PTS in peripherally advanced nonsmall cell lung cancer. Patients received 1250 mg/m of GEM on day 1, 8, and 75 mg/m of CIS on day 1, every 21 days for four cycles. PTS was injected intratumorally through percutaneous injection under computed tomography guidance on days 5, 12, 15, and 18 of cycle 1, and repeated on days 5 and 12 of cycle 2 if a less than 50% necrotic area was achieved after the first cycle according to the computed tomography scan. Twelve (46.2%) patients had metastatic disease, whereas 14 (53.8%) patients had stage IIIB disease. All 26 patients were assessable for response. Overall response rate by intention-to-treat was 53.8% (95% confidence interval: 34.6-73.0%). Median progression-free survival and overall survival were 6.5 months (95% confidence interval: 3.8-10.2 months) and 14.5 months (10.0-18.0 months), respectively. One-year and 2-year survivals were 57.7 and 22.4%, respectively. The grade 3-4 hematologic adverse events were neutropenia in six patients (23.1%), anemia in three (11.5%), and thrombocytopenia in four patients (15.4%). Nonhematologic toxicities were generally mild and usually not dose-limiting. Although grade 1-2 emesis occurred in nine patients (34.6%), only one had grade 3 vomiting. Grade 1-2 cough, local pain, and peripheral neurotoxocity developed in 12 (46.2%), three (11.5%), and five (19.2%) patients, respectively. There were no treatment-related deaths. GEM/CIS chemotherapy with concurrent PTS local injection therapy is a well-tolerated modality with potential activity in previously untreated peripheral advanced nonsmall cell lung cancer patients.