  In this contribution, we discuss three situations in which complete
integrability of a three dimensional classical system and its quantum version
can be achieved under some conditions. The former is a system with axial
symmetry. In the second, we discuss a three dimensional system without spatial
symmetry which admits separation of variables if we use ellipsoidal
coordinates. In both cases, and as a condition for integrability, certain
conditions arise in the integrals of motion. Finally, we study integrability in
the three dimensional sphere and a particular case associated with the Kepler
problem in $S^3$.
