Background : Small cell lung cancer represents approximately 20% of all carcinomas of the lung, and is recognized as having a poor long term outcome compared to non-small cell lung cancer. Therefore, this study investigated the prognostic factors in small cell lung cancer patients in order to improved the survival rate by using the proper therapeutic methods. Material and method : The clinical data from 394 patients who diagnosed with small cell lung cancer and treated from 1993 to 2001 at the Kosin University Gospel Hospital, were analyzed. Result : There were 314 male patients (79.7%), and 80 female patients (20.3%). The number of those with limited disease was 177 (44.9%), and the number of those with extensive disease was 217 (55.1%). Overall, 366 out of 394 enrolled patients had died. The median survival time was 215 days (95% CI : 192-237days). The disease stage, Karnofsky performance state, 5% body weight loss for the recent 3 months, chemotherapy regimens, and the additive chest radiotherapy were identified as being statistically significant factors for the survival time. The median survival times of the supportive care group, one anticancer therapy, and two or more treatment groups were 17 days, 211 days, and 419 day, respectively (p<0.001). These data emphasize the importance of anticancer treatment to improve survival time for patients. The group of concurrent chemoradiotherapy (30 patients) showed significantly longer survival time than the group given sequential chemoradiotherapy (55 patients) (528 days versus 373 days, p=0.0237). The favorable prognostic factors of laboratory study were groups of leukocyte =8,000/mm3, ALP=200 U/L, LDH=450 IU/L, NSE=15 ng/mL, s-GOT=40 IU/L. In extensive disease, there was no difference according to the number of metastatic site. However, the median survival time of patients with ipsilateral pleural effusion had longer than patients having other metastatic sites. According to the survey periods, three groups were divided into 1993-1995, 1996-1998, and 1999-2001. The median survival time was significantly prolonged after 1999 in comparison to previous groups (177 days, 194 days, 289 days, p=0.001, 0.002, respectively). Conclusion: Disease stage and 5% body weight loss for recent 3 months at diagnostic state were significant prognostic factors. In addition, the performance status, serum ALP, LDH, NSE, CEA levels also appear to be prognostic factors. The survival time of those patients with small cell lung cancer has been prologned in recent years. It was suggested that the used of the EP (etoposied and cisplatin) chemotherapy method and concurrent chemoradiotherapy for patients with a limited stage contributed to the improved survival time.