Abstract: Catalysts comprising a medium to large port zeolite modified by the oxide or acid of an element selected from the group consisting of Group IIIA to VIIA elements and, a Fischer-Tropsch catalyst wherein the ratio of zeolite to Fischer-Tropsch component is from about 0.1 to 50:1 can be employed to produce fuel grade saturated gaseous hydrocarbons from synthesis gas. A process is employed which includes the step of contacting synthesis gas over the foregoing catalyst at a reaction temperature of from about 100.degree. C. to 500.degree. C. and at a pressure of from about one atmosphere (0.1 MPa) to about 200 atmospheres (20 MPa) and at a gas hourly space velocity of from about 10 to 100,000. A method is also provided for the preparation of the combination catalyst. The catalyst and process for its use results in a small liquid aromatic product also being formed which is suitable for forming gasoline. Olefins and oxygenates are essentially eliminated.