A combustion mode transition control for controlling a transition between a homogeneous-charge compression-ignition (HCCI) combustion mode and a spark-ignition (SI) combustion mode includes slowly transitioning intake and exhaust camshafts from initial phase settings corresponding to one of the HCCI and SI combustion modes to target phase settings corresponding to the other of the HCCI and SI combustion modes. An ignition spark timing and an injected fuel mass are coordinated with the transitioning of the intake and exhaust camshaft phase settings to substantially maintain engine load continuity during the transitioning of the intake and exhaust camshaft phase settings.