Abstract The elution profiles of 17 aminoacyl-tRNA synthetases from chromatography of 149 000 × g supernatant on Sephadex G-200 were determined as well as the influence of different methods of homogenization and of chromatography on DEAE-cellulose on the elution profiles. With gentle homogenization all synthetases were eluted in the void volume in four different peaks, containing (a) leucyl- and phenylalanyl-, (b) lysyl-, prolyl-, isoleucyl-, methionyl-, glycyl- and valyl- (c) arginyl-, alanyl- and asparaginyl- and (d) aspartyl-, histidyl-, seryl-, threonyl-, glutaminyl- and tyrosyl-tRNA synthetases. With less gentle homogenization, peaks of lower molecular weight appeared. More than two peaks for each aminoacyl-tRNA synthetase were never found. Of the aminoacyl-tRNA synthetases examined, alanyl-, arginyl-, aspartyl-, leucyl- and lysyl-tRNA synthetases were not inactivated by chromatography on DEAE-cellulose, whereas phenylalanyl- and seryl-tRNA synthetases lost 60% of their activity.