Background: Azacytidine was recently approved for treatment of adult patients with acute myeloid leukemia (AML) not elegible for intensive chemotherapy, for patients with chronic myelomonocytic leukemia (CMMoL) and myelodysplastic syndromes (MDS). Prior to azacytidine, patients usually received low-dose ara-C, blood transfusions or growth factors with limited success. Here we present a single institution experience of patient treatment with azacytidine. Patients and treatment: From July 2009 to December 2012 we treated 48 patients. Twenty patients had AML, nine refractory anemia (RA), eight refractory anemia with excess blasts (RAEB) type 1, eight RAEB type 2 and three had CMMoL. For various reasons, 17 patients received only one cycle of azacytidine: eight with AML, three with RA, three with RAEB-1, one with RAEB-2 and two with CMMoL. Four patients received only two cycles of azacytidine: two with AML, one with RAEB-1 and one with RAEB-2. We used standard protocol of azacytidine 75 mg/m2 s.c. for seven days every 28 days. Treatment results were expected after three to four cycles of azacytidine. Results: Thirty-two patients received three or more cycles of azacytidine. Out of 13 AML patients, seven (54 %) went into remission and six (46 %) failed therapy. Out of seven RA patients, six (86 %) went into remission, one patient had partial remission and one patient failed therapy. Five (100 %) patients with RAEB-1 as well as two (67 %) patients with RAEB-2 failed therapy. One patient with RAEB-2 had partial remission. Cytogenetic remission was seen only in one patient with RAEB-2. Only one (25 %) patient with CMMoL responded to therapy. Responders decreased their dependance to blood and platelet transfusions after three or four cycles of azacytidine. Conclusions: Azacytidine was succsessful in half of the treated patients with AML, MDS and CMMoL, who received at least three cycles of therapy. Appropriate patient selection for azacytidine treatment is mandatory.