Abstract: L-malic acid is separated by means of electrodialysis from reaction mixtures derived from biotechnical conversion of fumarate into L-malate. Fumaric acid present in the acid concentrate from the dialysis is separated from L-malic acid without precipitation reactions using stepwise crystallization. Crystallized L-malic acid is produced in high purity and large yield. The alkali concentrate obtained during electrodialysis is recycled back into the biotechnical conversion. The process operates without appreciable losses of valuable materials and is very economical.