Aim: Acute pancreatitis (AP) is an inflammatory disorder, the incidence of which has been increasing over recent years. Mean platelet volume (MPV) is an index of platelet activation and influenced by inflammation. The objective of the present study is to assess whether MPV would be convenient parameters for predictor factor of patients with AP. Materials and methods: A total of 140 AP patients (male/female: 63/77) and 70 healthy subjects (male/female: 23/47) were enrolled in this study. The following data were extracted from the hospital medical records, including age, sex, platelet count, MPV, were recorded at the time of admission and as well as at the 1st day of remission of the disease. Results: Mean platelet volume levels at onset and remission of AP were 7.8 ± 1.6 and 7.7 ± 0.9 respectively, and there was no statistically significant difference between these groups. Platelet count at onset and remission of AP and control subjects was 203 ± 74 × 103/μl, 234 ± 76 × 103/μl and 251 ± 87 × 103/μl, respectively, and there was statistically significant difference between these groups. Platelet count at onset and remission of AP was statistically lower than control subjects. Conclusion: Some studies in literature suggest that MPV might be a useful parameter to be used as an indicator for AP and a prognostic factor for AP, but, in this study, it was revealed that MPV values do not change at AP compared with controls. Therefore, further prospective studies investigating the factors affecting the platelet size are required to determine whether MPV has a clinical implication and for predictor value of patients with AP.