The effects of air pollution on the marbles of the Roman temple of Augustus in Ankara (Turkey) have been investigated. Samples taken from the exfoliations have been examined by x-ray powder diffraction optical microscopy scanning electron, microscopy coupled to an edax system and limited chemical analysis. Gypsum formation is described. Deterioration is discussed in relation to temple of Augustus. Atmospheric parameters and pollution data. The building of a roof to protect against rain is suggested as an immediate precaution. Photomicrographs 7 references.