This volume contains the Proceedings of the Third International Conference on Navier-Stokes Equations and Related Nonlinear Problems. The conference was held in Funchal (Madeira, Portugal), on May 21-27, 1994. In addition to the editor, the organizers were Carlos Albuquerque (FC, University of Lisbon), Casimiro Silva (University of Madeira) and Juha Videman (1ST, Technical University of Lisbon). This meeting, following two other successful events of similar type held in Thurnau (Germany) in 1992 and in Cento (Italy) in 1993, brought together, to the majestically beautiful island of Madeira, more than 60 specialists from all around the world, of which about two thirds were invited lecturers. The main interest of the meeting was focused on the mathematical analysis of nonlinear phenomena in fluid mechanics. During the conference, we noticed that this area seems to provide, today more than ever, challenging and increasingly important problems motivating the research of both theoretical and numerical analysts. This volume collects 32 articles selected from the invited lectures and contributed papers given during the conference. The main topics covered include: Flows in Unbounded Domains; Flows in Bounded Domains; Compressible Fluids; Free Boundary Problems; Non-Newtonian Fluids; Related Problems and Numerical Approximations. The contributions present original results or new surveys on recent developments, giving directions for future research. I express my gratitude to all the authors and I am glad to recognize the scientific level and the actual interest of the articles.