In 93 patients with inoperable non-small cell lung carcinoma who underwent chemotherapy including cisplatin, the prognostic value of 9 factors were determined using Cox's proportional hazard model. Univariate analysis revealed that patients with a performance status of grade 2 (p < 0.01) or 3 (p < 0.05), those with stage IV disease (p < 0.05), those with a serum neuron specific enolase (NSE) level > 7.0 ng/ml (p < 0.001), and those with a low serum albumin level (p < 0.05) had a significantly worse prognosis. Multivariate analysis showed that a performance status of 2 or 3 and a high NSE serum level were associated with a significantly worse prognosis. More attention should be paid to the serum NSE level in patients with non-small cell lung carcinoma, because it not only reflects the tumor volume, but is also a prognostic factor which is dependent on individual tumor characteristics.