Abstract: A method of repairing an underground large-diameter pipe having an inner surface includes first supporting with props inside the pipe spaced inward from its inner surface a lining having a shape conforming to that of the inner surface and then injecting a hardenable mass into the space between the inner surface and the lining and substantially completely filling this space with the mass. The mass is then cured and the props are removed. Then the cycle can be repeated for the next lining section. The lining is made of a durable synthetic resin, polyvinylchloride or high-density polyethylene.