A reliable knowledge of the composition of archaeological bronzes for major and trace elements is of primary interest for the archaeologist. The composition of the metal artifacts gives information on the ancient technological knowledge and may help to distinguish between prehistoric cultural traditions. Pieces of bronzes from two pre-roman sites in Spain with different cultural traits have been analysed by ion beam analytical techniques (PIXE, PIGE and RBS) and Auger electron spectroscopy (AES). Joint use of these techniques has been found to be useful as they give complementary information on elemental composition and chemical state. The possible disturbance of the patina as a mask for the determination of the original underlying bronze composition has also been studied.