The present invention comprises bicyclic aryl-sulfonic acid [1,3,4]-thiadiazol-2-yl-amides, their functional derivatives thereof as well as their physiologically acceptable salts and pharmaceutical compositions thereof that exhibit peroxisome proliferator activated receptor (PPAR) PPARdelta and PPARgamma agonist activity. The structure of the compounds of the invention are defined by Formula I below, ##STR00001## wherein the various substituents are defined herein, including their physiologically acceptable salts. Processes for the compounds preparation are also disclosed. The compounds are suitable for the treatment of fatty acid metabolism and glucose utilization disorders, disorders relating to insulin resistance are involved as well as demyelinating and other neurodegenerative disorders of the central and peripheral nervous system.