A method is described for systematically deriving steady-state rate equations. It is based on the schematic method of King & Altman [J. Phys. Chem. (1956) 60, 1375-1378], but is expressed in purely algebraic terms. It is suitable for implementation as a computer program, and a program has been written in FORTRAN IV and deposited as Supplementary Publication SUP 50078 (12 pages) at the British Library (Lending Division), Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1977) 161, 1-2.