9-beta-D-Fucopyranosyladenine (1) has weak antileukemic activity against L1210 cells grown in culture. Several new 6'-deoxyhexopyranosyladenine nucleosides were synthesized by standard procedures and assayed for activity. The new nucleosides were 9-(6-deoxy-beta-D-glucopyranosyl)adenine (2), 9-(6-deoxy-beta-D-allopyranosyl)adenine (3), 9-(6-deoxy-alpha-L-talopyranosyl)adenine (4), 9-alpha-D-rhamnopyranosyladenine (5), and 9-(6-deoxy-alpha-L-idopyranosyl)adenine (6). In addition, 9-(6-deoxy-alpha-L-sorbofuranosyl)adenine (7) was isolated from the same preparation as 6. None of the new nucleosides 2-7 had activity against L1210 cells in culture. A number of other known nucleosides related in structure to 1 were also tested for activity. One of these, 9-alpha-L-arabinopyranosyladenine, had activity, but was significantly weaker than 1.