A control apparatus for a power transmitting system of a hybrid vehicle including (a) a differential portion which has a differential mechanism operatively connected to an engine and a first electric operatively connected to the differential mechanism, and a differential state of which is controlled by controlling an operating state of the first electric motor, and (b) a differential-state switching device which is incorporated in the differential mechanism and which is operable according to a differential-state switching condition, to switch the differential mechanism between a differential state in which the differential mechanism is operable to perform a differential function and a non-differential state in which the differential mechanism is not operable to perform the differential function, the control apparatus including a differential-state-switching-condition changing portion operable to change a differential-state switching condition for switching the differential-state switching device to switch the differential mechanism between the differential and non-differential states, when a temperature of the power transmitting system is lower than a predetermined threshold value.