In this study, the effects of ascorbic, folic, and salicylic acid treatments on postharvest quality losses in 'Franklin F1' Brussels sprouts stored at 4°C for 28 days were investigated. Weight loss (%), color values (L*, a*, b*), total soluble solids (TSS, %), pH, titrable acidity (TA, %), total chlorophyll (mg/g), and CO2 concentration (ppm) were all measured at 7-day intervals. When the findings were compared to the control group, it was observed that all of the treatments were effective in reducing losses in the examined properties. At the end of the storage period, it was found that ascorbic acid was the most effective in terms of weight loss, pH, and TA features, salicylic acid in terms of L* value, and folic acid in terms of preventing pH, total chlorophyll, and CO2 concentration changes. There has been no research on the effects of ascorbic, folic, and salicylic acid treatments in Brussels sprouts during the post-harvest period, and the goal of this study is to fill in the gaps in the literature and give light on future research. It is thought that determining the appropriate doses of the treatments performed in future studies, as well as examining the efficiency of the treatments in more detail, will be beneficial.