The present invention provides a chromatographic separation process for recovering a polyunsaturated fatty acid (PUFA) product from a feed mixture which is a fish oil or which is derived from fish oil, which process comprises the steps of: (i) purifying the feed mixture in a chromatographic separation step, to obtain a first intermediate product; and (ii) purifying the first intermediate product obtained in (i) in a simulated or actual moving bed chromatographic separation step, to obtain a second intermediate product; and (iii) purifying the second intermediate product obtained in (ii) in a simulated or actual moving bed chromatographic separation step, to obtain the PUFA product; wherein an aqueous organic solvent is used as eluent in each separation step; saturated and/or monounsaturated fatty acids present in the feed mixture are removed in the first separation step; the PUFA product is separated from different components of the feed mixture in steps (ii) and (iii); and the PUFA product obtained in the third separation step contains EPA or an EPA derivative in an amount greater than 90 wt %.