The preparation and antitumor activity of a series of 3'-alkylamino and 3'-dialkylamino analogues of amsacrine are reported. The results support previous work suggesting that the presence of electron-donating groups in the 3'-position of the anilino ring substantially enhance the antitumor activity of amsacrine analogues, possibly by the provision of high levels of electron density at the 6'-position. The alkylamino derivatives generally possess tighter DNA binding, higher levels of in vitro and in vivo antileukemic activity, and greater aqueous solubility than the corresponding amsacrine analogues.