Long noncoding RNAs (lncRNAs) are newfound noncoding RNAs that are greater than 200 nucleotides in length. They have emerged recently as major players in governing fundamental biological processes. However, the expression level of lncRNAs and their clinical significances are not well understood. To investigate the lncRNA expression in gastric cancer, real-time reverse transcriptase-polymerase chain reaction was conducted. Then, the association between the level of AC096655.1-002, one of lncRNA, in gastric cancer tissues and the clinicopathological features of patients with gastric cancer was further analyzed. Receiver operating characteristic (ROC) curve was constructed to evaluate the diagnostic values. The results showed that AC096655.1-002 was significantly downregulated in gastric cancer tissues compared with paired adjacent non-tumorous tissues (P < 0.001). Its expression level was significantly correlated with lymph node metastasis (P < 0.001), distant metastasis (P < 0.001), tumor-node-metastasis stages (P < 0.001), and differentiation (P = 0.030). The area under the ROC curve of AC096655.1-002 was up to 0.731. For the detection of gastric cancer, the use of AC096655.1-002 showed a remarkable improvement compared with the use of serum carcinoembryonic antigen. These results indicated that lncRNA AC096655.1-002 may be a potential biomarker in the diagnosis of gastric carcinoma.