Abstract: Objective To explore the efficacy and safety of domestic pemetrexed combined with carboplatin as the first-line treatment in elderly patients with advanced lung adenocarcinoma. Methods From July 2009 to December 2011，clinical data of 49 elderly（≥65 years）patients with Ⅳ stage lung adenocarcinoma were analyzed retrospectively. Forty-nine patients received domestic pemetrexed 500mg／m2 iv, d1 and carboplatin（AUC=5）iv, d1. Every 3 weeks was a cycle. The recent efficacy was evaluated every 2 cycles and longterm efficacy was followed up. The relevant indexes were analyzed. The side effects were recorded each cycle. Results Among 49 patients，48 patients were treated with pemetrexed combined carboplatin at least 2 cycles. The response rate and disease control rate of the 48 patients were 22.9％ and 64.6％，respectively. The median progression free survival（PFS）was 6.5 months（95％CI：5.7-7.3）， and median overall survival（OS） was 11.3 months（95％CI：10.6-11.9）. According to age，sex，ECOG score，smoking，metastasis numbers，bone metastasis， malignant pleural effusion and brain metastasis，patients were divided into groups. There were significant differences in RR，PFS or OS between groups of ECOG score，smoking and metastasis numbers（P＜0.05）. The major side effects were bone marrow suppression and gastrointestinal toxicity. The adverse events were manageable at grade 1-2. Conclusion Domestic pemetrexed in combination with carboplatin is effective and well tolerated as the first-line treatment in elderly patients with advanced lung adenocarcinoma.