The increasing use of architectural concrete is causing greater attention to be placed on good construction practices. The difficult shapes, low slump concrete mixes, and high concentration of steel reinforcement often needed require much attention and careful planning. Although most contractors realize the need for extra care something occasionally goes wrong and when the forms are stripped the concrete has a higher percentage of voids than does Swiss cheese. This seems most likely to happen at times when everyone is especially concerned that nothing delay the project. The contractor who has this experience has only two choices: to remove and recast the defective section, or to repair it. Frequently it is in the best interest of both the contractor and owner to have the section repaired, but too many architects will not permit repair of cast-in-place architectural concrete. Although it is true that sometimes removal and recasting are better and less expensive than repair, most defective architectural concrete can be repaired successfully. The pictorial account found in the article of repairs to a pair of buttresses illustrates some of the most important of the steps in the process.