Two types of CeO 2 -modified Ni/Al 2 O 3 catalysts were prepared by a consecutive impregnation method with different sequences in the impregnation of Ni and CeO 2 , and their performance in autothermal reforming (ATR) of isooctane was investigated. Catalysts prepared by adding CeO 2 prior to the addition of Ni, Ni/CeO 2 -Al 2 O 3 , produced larger amounts of hydrogen than those obtained using catalysts prepared by adding the two components in an opposite sequence, Ni-CeO 2 /Al 2 O 3 . The results of H 2 chemisorption and temperature-programmed reduction revealed that added CeO 2 increased the dispersion of the Ni species on Al 2 O 3 and suppressed the formation of NiAl 2 O 4 in the catalyst such that large amounts of Ni species were present as NiO, the active species for the ATR. The elemental and thermogravimetric analyses of deactivated catalysts indicated that Ni/CeO 2 -Al 2 O 3 , which showed a longer lifetime than Ni-CeO 2 / Al 2 O 3 , contained lesser amounts and different types of coke on the surface.