A process for the preparation of flame-resistant soft polyurethane foams which produce less smoke in the event of fire involves reacting a) an organic polyisocyanate and/or a modified organic polyisocyanate with b) a high-molecular-weight compound containing at least two reactive hydrogen atoms and, if desired, c) a chain extender and/or crosslinking agent, in the presence of d) a mixture of flameproofing agents which contains: di) melamine dii) expandable graphite and, if desired, diii) at least one further flameproofing agent, preferably a modified or unmodified ammonium polyphosphate, e) a blowing agent, f) a catalyst and, if desired, g) assistants and/or additives, and melamine/expandable graphite/polyether-polyol dispersions which are suitable for this purpose.