In Allium cepa (cv. Creamgold), A. cepa (cv. Bunching Onion), A. porrum (leek) and A. sativum (garlic), fructans were the only nonstructural carbohydrates detected apart from glucose, fructose and sucrose. No starch or members of the raffinose series of oligosaccharides were detected. Both cultivars of A. cepa, and A. porrum had fructan polymers of the same length. The maximum DP (degree of polymerization) detected was 12. However, maximum carbohydrate concentration occurred in DP5 for A. cepa (cv. Bunching Onion) and DP12 for A. porrum. A. sativum was different from the other species in that larger polymers were present, reaching a DP of 50. The trisaccharides, 1F-fructosylsucrose and 6G-fructosylsucrose were found in all species. A. cepa and A. sativum contained similar fructan: fructan frutosyltransferases. Enzymes from both plants transferred fructosyl residues from trisaccharide to form tetrasaccharide and sucrose as the major products. This self-transfer predominated even in the presence of higher molecular weight acceptor molecules.