The aim of this study was to assess the effect of a combined 14-day treatment with rosuvastatin (10 mg/kg) and fluoxetine (10 mg/kg) on selected biochemical parameters of oxidative stress in the blood of rats. The activity of glutathione peroxidase (GPX), glutathione reductase (GR) and the total antioxidant status (TAS) were determined. A combined 14-day treatment with rosuvastatin and fluoxetine significantly increases glutathione peroxidase and glutathione reductase activity and decreases the level of TAS. Rosuvastatin administered to rats caused a decrease in the glutathione peroxidase activity and an increase in the glutathione reductase activity but did not affect the level of TAS. A 14-day treatment with fluoxetine exerted practically no effect on the investigated parameters of oxidative stress in rats. The abovementioned changes in the biochemical parameters after the combined treatment with rosuvastatin and fluoxetine may imply an imbalance in prooxidant and antioxidant levels in the combined treatment with rosuvastatin and fluoxetine.