A catalyst comprising at least one support, at least one element from groups 8, 9 or 10 of the periodic table, at least one element from group 14 of the periodic table, at least one element from group 13 of the periodic table, at least one alkali or alkaline-earth metal, and, optionally, at least one halogen in an amount in the range from 0 to 0.2% by weight with respect to the total catalyst weight, the catalyst being characterized in that the accessibility of the element from groups 8, 9 or 10 is more than 50%. The invention also concerns a process for preparing a catalyst and the use of the catalyst in a process for dehydrogenating paraffins containing 3 to 22 carbon atoms per molecule.