BACKGROUND Amyloidosis is a protein-misfolding disease characterized by the deposition of aggregated proteins in the form of abnormal fibrils that disrupt tissue structure, ultimately causing disease. Amyloidosis is very frequent in untreated familial Mediterranean fever (FMF) patients and it is the most important feature that determines the prognosis of FMF disease. The mean platelet volume (MPV) in FMF has been previously studied. However, whether MPV level in FMF patients is lower or higher compared to healthy controls remains a topic of ongoing debate. In this study, we aimed to investigate MPV values and to assess the correlation between MPV and proteinuria in patients with AA amyloidosis and AA amyloidosis secondary to familial Mediterranean fever (AA-FMF) through a retrospective chart-review. MATERIAL AND METHODS This study was carried out on 27 patients with AA amyloidosis, 36 patients with AA amyloidosis secondary to FMF (a total of 63 patients with AA), and 29 healthy controls. There was no statistically significant difference between the AA patients and the control group (p=0.06) or between the AA-FMF group and the control group in terms of MPV values (p=0.12). RESULTS We found a statistically significant negative correlation between MPV and thrombocyte count in all groups (p<0.05 for all groups), but there was no correlation between MPV and proteinuria levels in AA patients (p=0.091). CONCLUSIONS While similar results also exist, these findings are contrary to the majority of previous studies. Therefore, further controlled clinical prospective trials are necessary to address this inconsistency.