Aluminum-pillared clays based on synthetic beidellite have been prepared by exchanging hydrothermally synthesized beidellite with partly hydrolyzed aluminum nitrate solution followed by calcination. It is shown that a catalyst containing 50 wt% amorphous silica and 50 wt% pillared beidellite loaded with 0.8 wt% Pt has an n-heptane hydroconversion comparable to a commercially available silica-alumina and does not significantly deactivate with increasing time on stream (within 14 h).