Background: When cancer is terminal and cancer-directed therapy has no value, the goal of treatment is to improve the quality of life (QoL). The current work proposed to assess the prognostic nutritional index (PNI) on QoL in patients with terminal cancer. Methods: The medical files of terminal cancer patients who died between February 2012 to April 2017, retrospectively reviewed to evaluate the PNI on their QoL. Presence of Emergency Department (ED) visits >1, hospital admission through the ED, and intensive care unit death is considered a representative for poor QoL. Results: A total of 828 patients with terminal cancer were enrolled. The median age was 62 years, ranged from 18-107 years. The frequency of primary cancer sites was colorectal cancer in 146 patients (17.6%), hepatobiliary in 123 (14.9%), lung cancer in 112(13.5%), breast cancer in 106 (12.8%), and genitourinary in 79 (9.5%). The value of PNI experienced different levels among cancer types with mean value was 32.9 ±6.7. High PNI was statistically significantly associated with hospital admission through the outpatient clinic (OPC), ED visits ≤ 1, onward death, and survival > 2 weeks (P = 0.005, P=0.015, P=0.04 and P<0.001), respectively. While forfeiting the statistically significant with age, sex, and primary cancer sites (P =0.3, P =0.6, and P =0.5), respectively. Conclusion: PNI is a simple and applicable marker associated with improved Qol in patients with terminal cancer.