The state of the iris has been studied in 817 persons, of them in 150 workers of oil-industry, in eye office conditions. Iridodiagnostics was performed in one and the same person using two methods: with the help of a slit lamp “SL-56” and a magnifying glass. For topic diagnostics, a scheme of projection zones of the iris was used, proposed by Vida and Deck. The results obtained were compared with clinical diagnosis made in the out- or in-patient’s departments by internist, gynaecologist or other specialists. In 80.1% of the subjects a pathologic sign situated in the corresponding zone of the iris has almost precisely indicated the affected organ. Among the whole number of subjects in 37% of persons the revealed pathologic signs of the iris have indicated the physicians to the organ where the disease had not been earlier diagnosed.