The synthesis and biological activity of hybrids 8-18 prepared combining alpha-methylene-gamma-butyrolactones and alpha-bromoacryloylamides have been described and their structure-activity relationships discussed. All these heterobifunctional compounds demonstrate good antileukemic activity, significantly superior to that of both alkylating units alone. Using the human leukemia HL-60 cell line, selected compounds 10, 11, 13, and 17 were found to induce morphological changes and internucleosomal DNA fragmentation characteristic of apoptotic cell death.