Chromium (III) ions influence significantly carbohydrate-lipid metabolism causing in diabetic subjects an optimalisation of insulin action, increase of lipid alteration, decrease body weight and free fatty acids plasma level. The aim of the present study was to describe changes in β-oxidation of fatty acids and gene expression following chromium supplementation. The experiments were performed in mouse myoblast C2C12 cell line over 4 days differentiation. Chromium was added to medium (DMEM), as chromium chloride (CrCl₃) or chromium picolinate, in 1 and 10 µgCr³⁺/L concentrations. Beta-oxidation of fatty acids activity was measured after 1, 3, 6, or 48 h. incubations. Introduction of chromium 1 µgCr³⁺/L to cell culture resulted intensification of fatty acids oxidation after 1 and 3 h (picolinate, p < 0,001) and 1, 3, and 6 h (chloride, p < 0,001) incubation. We observed higher stimulation effect along chromium chloride administration (about 50% of control value) than chromium picolinate (25% of control value). After 48h incubation decrease of fatty acids oxidation were noticed. The influence of chromium chloride (10 µgCr³⁺/L) supplementation on gene expression was examined using microarray SuperArray technique. Chromium added caused increase in 22 genes expression over 4h while only 2 increase and 2 decrease over 24h incubation in compare with control. The results in these studies showed positive effect of chromium supplementation on activity of β-oxidation. Results from microarray analysis indicate chromium interaction on signaling insulin pathway, also on transcription level. Increased expression of genes engaged in lipid metabolism and genes activated by peroxisome proliferator–activated receptor PPAR suggest permanent effect caused by chromium ions.