This review is concerned with systematization of nanotechnologies in heterogeneous catalytic processes of chemistry, petroleum chemistry, and petroleum refining. Manifestation of the size effect in catalytic nanoreactors, catalytic and physicochemical properties of the nanosized active component of supported heterogeneous catalysts, nanostructured porous crystals (molecular sieves), and catalytically active nanosized particles has been discussed. The formation of a new trend in nanotechnologies, namely, nanoheterogeneous catalysis, has been substantiated on the basis of original research and analysis of the experimental data in the literature.