The present paper is the twentieth communication in a series of review papers on the development of antituberculotics and the ninth communication summarizing the work in the development of antituberculotics within recent 15 years. The first seven communications were devoted to heterocyclic compounds, the eighth to substances containing an alkylsulfanyl group in the pharmacophore. The present paper summarizes information about cyrboxylic acids, their amides, anilides, hydrazides, thioamides, thioanilides, thiohydrazides, and amidines. The communication includes papers published after 1980 in order to link up with a review paper devoted to the same topic published in the present series in 1982.