Abstract Background Nab-paclitaxel plus gemcitabine (AG) and modified FOLFIRINOX (FFX) are two systemic therapies that have been widely used as standard first-line chemotherapy regimens in metastatic pancreatic cancer. However, since there is no clinical trial to directly compare the efficacy and safety of the two regimens, it is not clear which regimen is more effective. In this study, we aim to examine and compare the efficacy and safety of AG and FFX as first-line chemotherapy regimens in Chinese patients with metastatic pancreatic cancer in a real-world setting. Methods We retrospectively evaluated the outcomes of 44 patients who were diagnosed with metastatic pancreatic cancer and were treated with either AG (n = 24) or FFX (n = 20) as first-line chemotherapy between March 2017 and February 2022 at Zhongnan Hospital of Wuhan University. Prognostic nutrition index (PNI) was calculated based on the serum albumin level and peripheral lymphocyte count. According to the optimal cutoff value of PNI, patients were divided into low PNI group (PNI