Inhibition of programmed cell death (apoptosis) is associated with increased tumor aggressiveness. We hypothesized that a novel apoptosis inhibitor gene, antiapoptosis clone 11 (AAC-11), may be expressed in tumors of patients with non-small cell lung cancer (NSCLC) and affect their clinical outcome. Expression of AAC-11 messenger RNA was evaluated by reverse transcription polymerase chain reaction (RT-PCR) in 94 non-small cell lung carcinomas and adjacent histologically normal lung samples. The data was analyzed in reference to clinicopathological and survival data. AAC-11 transcripts were detected in 12 (12.7%) of the tumor samples, although five of paired normal lung samples showed very weak expression. There was no relationship between AAC-11 gene expression and age, gender, N or T-status. AAC-11 was preferentially expressed in squamous cell carcinoma (26.9% of squamous cell carcinoma vs. 7% of adenocarcinoma). The NSCLC patients with AAC-11 expression had significantly poor survival than the patients without AAC-11 expression (P=0.0360). Although the AAC-11 gene was not expressed in a majority of NSCLC tumors, we suggest that AAC-11 may predict poor survival.