Commercial flavoured olive and olive-sunflower oils and seed oils with particular nutritional properties (e.g. linseed, safflower, sunflower, sesame and rice oils) were analysed using a widespread analytical protocol to have information on their quality and chemical composition. The protocol involved traditional determinations (free acidity, peroxide value, UV and VIS spectrophotometric indices, and fatty acid composition) along with ¹H and ¹³C NMR analyses. Most of flavoured olive oils turned out to be lampante olive oils and not extra virgin as declared in the label on the bottle. In the case of olive-sunflower oils only a minor fraction of olive oil was revealed although these products are particularly expensive and the presence of olive oil is emphasized on the label. In some seed oils, refinement processes, not indicated on the bottle, were highlighted. Some compounds characteristic of specific seed oils were identified in the ¹H spectra.