The direct analysis of nickel sulfide fire assay buttons by UV laser ablation ICP-MS was used to determine the platinum-group elements and gold in the following reference materials: UMT-1, WPR-1, WMG-1, GPt-4, GPt-6 and CHR-Bkg. The instrument was calibrated with buttons prepared using quartz doped with the appropriate standard solutions. Analytical precision (RSD) was generally better than 10%, although occasional higher RSDs may infer local heterogeneities within nickel sulfide buttons. Good or excellent agreement was observed between analysed and reference material values except Ph in UMT-1 and WMG-1, which suffered an interference from copper. Detection limits calculated as 10s quantitation limits were Au (1.7 ng g(-1)), Pd (3.3 ng g(-1)), Pt (8.3 ng g(-1)), Os (1.3 ng g(-1)), Ph (1 ng g(-1)), Ru (5 ng g(-1)) and Ir (0.7 ng g(-1)).2214755