This paper is a study on the effects on the amounts of trace elements in case of possible repeat accidental or environmental exposure with fish oil biodiesel. For this purpose, 35 male Wistar albino rats were used in the study. Rats were divided into five groups. The first group was determined as the control group. The rats in this group were gavaged orally with 250 mg/kg sunflower oil. The rats in the second and third groups were administered by oral gavage of 250 mg/kg (D1) and 500 mg/kg (D2) diesel fuel mixed with equal amounts of sunflower oil, respectively. The rats in the fourth group were administered by oral gavage of 250 mg/kg fish oil biodiesel (F1) and the rats in the fifth group were administered by oral gavage of 500 mg/kg fish oil biodiesel (F2), both mixed with equal amounts of sunflower oil. At the end of the study, bioelement concentrations in the serum and the kidney, lung, and liver tissues were measured using inductively coupled plasma-optical emission spectroscopy. It was observed that serum Ca, Mg, and Sr concentrations were significantly (p<0.001) higher and Cu concentration was significantly (p<0.01) higher in the control group than in the biodiesel groups. Kidney Mg concentration was significantly (p<0.01) lower in the control group than in the diesel groups. Kidney Mg concentration was significantly (p<0.001) lower in the D2 group than in the F2 group. Kidney Mg concentration was significantly (p<0.01) lower in the control group than in the diesel groups. Lung Cd, Co, Cu, Cr, Na, and Zn concentrations were different significantly higher in the control group than in the other groups. Liver Al concentration was different significantly higher in the control group than in the other groups. Liver Ca concentration was significantly (p<0.05) higher in the control group than in the biodiesel groups. Serum and lung tissue bioelements concentrations were lower in diesel and biodiesel groups than in control group. Due to consumption for biochemical reaction of these elements, bioelements concentration could be low in diesel and biodiesel groups. Some trace elements concentrations in the kidney and liver were very high in the diesel groups. High concentration of these elements in the diesel groups might cause toxic effects. Fish oil biodiesel could be chosen as an alternative fuel instead of diesel fuel.