The oil refining industry operation is analyzed in order to estimate the future catalyst market trends. The refining catalyst market corresponding to the main catalytic processes is estimated taking into account the following information: (i) the average refining capacity increases for the main catalytic processes since 1999, (ii) the additional refining capacity due to future plans of construction and expansion of refineries and process units that will be added by 2005, and (iii) the past refining catalyst market behavior. From this information, we have determined for the main catalytic processes a global average factor, expressed as processed oil barrels per dollar of catalyst. According to our estimates, the global refining catalyst market will increase from $2.32 billion in 2001 to about $2.65 billion in 2005 (3.6% annual growth). Hydrotreating, fluid catalytic cracking, hydrocracking and isomerization represent about 74% of the total catalyst market and will grow by about $34, $32, $11 and $2.5 million per year, respectively. However, naphtha reforming catalyst market will not grow during 2001-2005. Higher catalyst spending growth is expected for the North America region ($27.5 million per year). (C) 2003 Elsevier B.V. All rights reserved.