Etioplasts from dark grown pea seedlings were isolated by isopycnic density centrifugation and short time centrifugation on continuous sucrose gradients. By this way mitochondria and microbodies were separated from the etioplast fraction. It could be shown that the etioplasts contain anthranilate synthetase, anthranilate-5'-phosphoribosyl-l-pyrophosphate phosphoribosyltransferase, N-5'-phosphoribosyl anthranilate isomerase, indole-3-glycerolphosphate synthetase, and tryptophan synthetase. Therefore the etioplasts are capable of carrying out the biosynthesis of tryptophan from chorismic acid via anthranilic acid, N-(5'-phosphoribosyl) anthranilic acid, 1-(o-carboxyphenylamino)-1-deoxyribulose-5phosphate, and in dole-3-glycerol phosphate.