Abstract: A process for the isomerization of C.sub.4 -C.sub.6 paraffins that uses a highly active catalyst to isomerize the feed in the presence of very little hydrogen. The process is characterized by good stability and high conversion with effluent hydrogen to hydrocarbon ratios of 0.05 or less. Continued operation at low hydrogen concentrations is made possible by the remarkably low coking tendency of the catalyst, especially during periods of temporary sulfur deactivation. The low hydrogen to hydrocarbon ratio simplifies the process and makes it cheaper to operate by eliminating facilities for the recovery and recycle of hydrogen.