Investigators have found the biological significance and the biosynthetic pathways of ether-linked lipids containing glycerol difficult to determine (1). Despite available knowledge concerning enzymes for the biocleavage (2,3), deacylation (4), acylation (5,6), and phosphorylation (7) of glyceryl ethers, the biosynthesis of the ether bond in these compounds has not previously been demonstrated in a cell-free system. This note describes an active enzyme complex capable of converting intact l-14C-labeled fatty alcohols into alkyl glyceryl ethers. The reaction has been demonstrated in whole homogenates and in microsomal-plus-supernatant fractions of transplantable preputial tumors in mice. These tumors are typical of neoplasms containing high quantities of alkyl ether linkages in both neutral- and phospho-glycerides (8). © 1969.