e20557 Background: Retrospective studies suggest that administering chemotherapy infusions in the morning can enhance treatment efficacy and mitigate side effects in non-small cell lung cancer (NSCLC) patients. However, the effectiveness of chronotherapy using pemetrexed plus platinum (AP) and paclitaxel plus platinum (TP) in advanced NSCLC chemotherapy remains unexplored. This study aims to evaluate the impact of AP and TP chrono-chemotherapy (CCT) on treatment response and adverse events in advanced NSCLC patients. Methods: We retrospectively analyzed 78 advanced NSCLC patients treated with AP (AP cohort) and 50 advanced NSCLC patients treated with TP (TP cohort) at Guangdong Second Provincial General Hospital from 2018 to 2021. Based on previous research, we classified patients who received chemotherapy infusions more than twice after 2:00 PM as the afternoon (PM) group, while the rest were categorized as the morning (AM) group. Treatment response was evaluated using the Response Evaluation Criteria in Solid Tumors Criteria V.1.1. The primary endpoint was progression-free survival (PFS). All adverse events were identified and graded according to the National Cancer Institute-Common Terminology Criteria for Adverse Events version 5.0. Results: In the AP cohort, the AM group exhibited a longer PFS compared to the PM group (AM vs. PM, n = 26 vs. n = 52, 43.0 vs. 13.0 months, p = 0.001). However, no significant difference was observed in PFS in the TP cohort (AM vs. PM, n = 23 vs. n = 27, 11.0 vs. 22.0 months, p = 0.501). Subsequent subgroup analysis in the AP cohort favored the AM group across all major subgroups for PFS treatment effect. In contrast, the TP cohort subgroups showed a PFS benefit only in the smoking patients of the PM group. Furthermore, the analysis of adverse reactions revealed similar incidences of any treatment emergent adverse events (TEAE) in both AP and TP cohorts (AM vs. PM, 92.3% vs. 86.5% in AP cohort and 95.7% vs. 100.0% in TP cohort), and grade 3 TEAEs (AM vs. PM, 34.6% vs. 21.2% in AP cohort and 39.1% vs. 29.63% in TP cohort). The most common adverse events were anemia (73.1%), leukopenia (57.7%), and elevated ALT (46.2%) in AP cohort and anemia (100%), leukopenia (65.2%), and hypoalbuminemia (47.8%) in TP cohort. Univariate and multivariate analyses indicated that afternoon infusion of AP chemotherapy (p = 0.009) was an independent prognostic factor for NSCLC. Conclusions: AP treatment administered in the morning may enhance PFS in advanced NSCLC, while TP remains unaffected. This suggests that CCT could potentially enhance the efficacy of individualized chemotherapy in advanced NSCLC.