Basic principles of the near-IR interferometry will be summarized in the first half of the the talk, as e.g., interferometric observables, beam combination, atmospheric turbulence and piston and fringe tracking. After presenting a few typical applications of interferometry, the ESO Very large Telescope Interferometer (VLTI) and its components will be described. Main results of interferometric projects achieved in collaboration of ESO and USP astronomers will close the talk.