BACKGROUND The aim of our study was to investigate the prognostic role of platelet/albumin ratio in patients treated under emergency conditions for peptic ulcer perforation (PUP). METHODS A retrospective study involving emergency patients who were operated for PUP was carried out. The patients were divided into 2 groups: PUP patients who died after surgical treatment (PUP-M) and PUP patients who survived after surgical treatment (PUP-S). The laboratory values of the patients were compared statistically. A P value of <.05 was considered statistically significant. RESULTS This cohort study consisted of 171 patients treated between June 2013 and December 2019. The mean age of the patients was 46.3 ± 20.5 years; and 33 (19.3%) patients were women. The age (P ≤ .001), platelet/lymphocyte ratio (P = .02), lactic dehydrogenase to albumin ratio (P ≤ .001), and platelet/albumin ratio (PAR; P ≤ .001) values were high and lymphocyte count was low (P = .006) in the PUP-M group. A positive correlation was determined between length of stay in hospital and age (P ≤ .001), lactic dehydrogenase/albumin ratio (P ≤ .001), platelet count (P = .044), and PAR (P ≤ .001). A substantial negative correlation was determined between length of stay in hospital and albumin count (P ≤ .001). CONCLUSIONS We determined a high preoperative PAR level in PUP patients who had undergone surgery as a negative prognostic parameter. PAR is a candidate biomarker for clinical practice.