This is the announcement of the Workshop on Random Walks, Particle Systems and Random Media, organized by the Facultad de Matemáticas, Pontificia Universidad Católica de Chile, FM-PUC and which will take place at the FM-PUC, Santiago de Chile, January 14-18, 2007. The organizers are Alejandro Ramírez of the FM-PUC and Vladas Sidoravicius of IMPA. The meeting will bring together mathematicians and mathematical-physicists working in the areas of random media, particle systems, random walks and reaction-diffusion equations.