  We introduce the concept of the {\em odd-frequency} Bose Einstein Condensate
(BEC), characterized by the odd frequency/time two-boson expectation value. To
illustrate the concept of odd frequency BEC we present simple classification of
pair boson condensates that explicitly permits this state. We point qualitative
differences of odd-frequency BEC with conventional BEC and introduce the order
parameter and wave function for the odd-frequency BEC.
