Tungstated and sulphated zirconium hydroxides produced by MEL Chemicals were used as a raw material for preparation of n-paraffins hydroisomerisation catalysts. The preparation involved forming of zirconium hydroxides with peptised aluminium hydroxide, thermal treatment and impregnation of the obtained supports with platinum hexachloric acid solution. The obtained catalysts, 0.5 wt.% Pt/(SO4/ZrO2 + Al2O3) and 0.5 wt.% Pt/(WO3/ZrO2 + Al2O3) were tested in a continuous flow process of n-cetane hydroisomerisation. It was occurred. that the applied doped zirconium oxides are mesoporous materials of relatively low pore volume in comparison with other known support materials, mesopores consists ca 80% of the total pore volume and 65% of the specific surface area. Addition of the alumina binder in the support forming stage increased pore volume and specific surface area of the obtained supports, mainly in the range of the mesopores diameter size. We have stated that the sulphated zirconia-alumina based platinum catalyst is highly active, low temperature hydrocracking catalyst; it gives total conversion (hydrocracking) of the feed at temperature process below 200degreesC. In our opinion the sulphated zirconia is not the suitable support component for the preparation of catalysts for hydroisomerisation of long chain hydrocarbons. The second of the prepared catalysts, the tungstated zirconia based one, is far more promising; it is less active but more selective in the n-paraffins hydroisomerisation process. Selection of the proper process parameters, hydrogen pressure and LHSV of the feed, makes it possible to attain 50-60% conversion with almost 90% hydroisomerisation selectivity. Products of hydrocracking (C-5-C-13 hydrocarbons) obtained at low conversion level (e.g. 28%) are mainly linear isomers (70%), but the increase in the conversion level up to 60-70% causes that products of hydrocracking were mainly branched isomers (approximate to 80%). (C) 2003 Elsevier B.V. All rights reserved.