A stabilized catalyst support having improved hydrothermal stability, catalyst made therefrom, and method for producing hydrocarbons from synthesis gas using said catalyst. The stabilized support is made by a method comprising treating a crystalline hydrous alumina precursor in contact with at least one structural stabilizer or compound thereof. The crystalline hydrous alumina precursor preferably includes an average crystallite size selected from an optimum range delimited by desired hydrothermal resistance and desired porosity. The crystalline hydrous alumina precursor preferably includes an alumina hydroxide, such as crystalline boehmite, crystalline bayerite, or a plurality thereof differing in average crystallite sizes by at least about 1 nm. The crystalline hydrous alumina precursor may be shaped before or after contact with the structural stabilizer or compound thereof. The treating includes calcining at 450.degree. C. or more. Preferred structural stabilizers can include cobalt, magnesium, manganese, manganese, zirconium, boron, aluminum, barium, silicon, lanthanum, oxides thereof, or combinations thereof.