D003 is a new product composed of a mixture of aliphatic fatty acids (C(24:0) to C(36:0)), which shows antiplatelet, antithrombotic, antioxidant, and cholesterol-lowering effects in experimental models and human beings. A gas chromatographic method using a DB-5 wide-bore column and 1-nonadecanoic acid as internal standard was developed and validated in order to determine D003 in 10 mg film-coated tablets. The acids were analysed as methyl esters derivatives, prepared using 5% aqueous HCl-methanol. Developed method was specific for the active principle, even when samples were subjected to stress conditions. Good linearity (correlation coefficient > 0.99) and accuracy (total average recovery = 100.29%) were proven over a range 50-150% of the nominal concentration. Within-day and intermediate precisions at the nominal dose (100%) were < 1.5%. Robustness was examined through an intralaboratory study, quantification and resolution were only affected by the injection volume increase and no other of the 7 operational changes evaluated affected the results. The method was suitable for quality control and stability studies of these tablets.