A series 18 patients (12 ANLL, 3 CML blastic crisis, 3 MDS) were treated with L-DAC for 14-21 days. Cytosine arabinoside was given by subcutaneus or intravenous injections at doses of 10 mg/m2 every 12 hr. Four complete and four partial remissions were achieved. Ten patients didn't respond to therapy and three of them died. The reported capability of cytosine arabinoside in inducing cellular differentiation couldn't be determined. However, since this regimen is easily applicable and economic, it can be preferable in some conditions.