The application of inductively coupled plasma mass spectrometry (ICP-MS) in the determination of the concentrations of trace elements in steel wires was investigated for the forensic discrimination of wires with different origins; the discrimination is carried out by comparing elemental compositions. Approximately 5 mg of a chip taken from the wire was accurately weighed and dissolved in a mixture of 100 μl HCl and 100 μl HNO₃ by heating at 80°C for 30 min. Following the addition of 100 μl of 5 μg/ml Y as an internal standard and 200 μl of 7M HCl, the matrix iron in the solution was removed by extraction with 200 μl MIBK. This extraction was repeated twice, and 300 μl of the aqueous phase was heated at 150°C for 1 h after the addition of 250 μl H₂SO₄. This solution was diluted to 25 ml by 1% HNO₃, and then the solution was used to determine the concentrations of Cr, Mn, Ni and Cu by ICP-MS. The measured values of these elements in NIST 16f (Steel Basic Open-Hearth) showed satisfactory good agreement with the certified values with RSDs from 1.0 to 2.1%. A comparison of the concentrations of the four elements determined by using the present method can be carried out to differentiate among the 21 possible pairs that can be formed from 7 wires produced by different manufacturers.