  We systematically investigate the possible molecular states composed of (1)
two spin-$\frac{3}{2}$ doubly charmed baryons, and (2) a pair of
spin-$\frac{3}{2}$ and spin-$\frac{1}{2}$ doubly charmed baryons. The
one-boson-exchange (OBE) model is used to describe the potential between two
baryons. The channel mixing effect is considered for the systems with the same
quantum number $(I(J^P))$ but different total spin ($S$) and orbital angular
momenta ($L$). We also study the channel mixing effect among the systems
composed of various doubly charmed baryons if they have the same quantum
number. Many of the systems are good candidates of molecular states.
