 Polyurethane foams, PUFs, have numerous applications due to their low density, thermal conductivity, mechanical properties, and petroleum-dependent production methods, which must adapt to regulations and consumer demands for renewable raw materials and new process technologies such as 3D printing. The fundamental aspects of PUF production are reviewed, along with the challenges and alternatives for improving sustainability through recycling and enhancing properties. This article was authored by Nuno V. Gama, Artur Ferreira, and Ana Barostimans.