In contrast to the well-developed conformational analysis of flexible nitrogen heterocycles, their conformational dynamics (pathways and rates of conformer inter-conversion) have been studied systematically only recently. The description of conformational dynamics derived by computational methods and supported by DNMR comprises basic monoazasystems, such as 4- to 6-membered azacycles and symmetric N-fused as well as N-bridged 4- to 6-membered ring bicyclic compounds. It appears that the dynamics of the monocycles (i.e., azetidines, pyrrolidines and piperidines) cannot be approximated by the dynamics of carbocyclic analogs due to a pyramidal nitrogen-inversion. For instance, concerted intramolecular motions (e.g., ring inversion – N-inversion) often predominate. For these and other systems, experimental kinetic barriers of conformational transformations (by DNMR) explicitly depend on the ring size and, surprisingly, on the alkyl substitution on the ring. However, only the geometry of the N- and of the adjacent C-pyramids determines the rate of nitrogen inversion. A detailed assessment for conformational dynamics of parent azacycles exposed several incorrect claims for particular cases (e.g., for some alkaloids) in the earlier literature.