This study is a sequential single blind-matched randomized trial on 18-70 years age new diagnosed patients that should be underwent antracyclin therapy in Toba clinic, Sari, Iran in 2013-2014. Written informed consent was obtained from all patients. Before initiation of chemotherapy, all patients underwent echocardiography by Vivid S5 and the images are stored for off line analysis. Left ventricular end diastole and end systole diameters are measured and LVEF is calculated by Simpson method. Evaluation for diastolic function is performed by Mitral inflow evaluation: pulse doppler (E,A wave, E/A ratio, E wave deceleration time, pulmonary veins flow and tissue doppler of Mitral valve annulus. E/e' ratio is calculated for determination of filling pressure. Patients are inserted alternately in control(no Enalapril)and intervention(Enalapril)groups. Age,sex and other variables are similar in two groups. In the intervention group, Enalapril is initiated at least 24 hours before first cycle of chemotherapy. Initial dose is 2.5mg BID(1.25mg in patients with systolic blood pressure up to 90-100mmHg). Dose is gradually increased each 3-6 days. If systolic blood pressure is more than 90 mmHg and serum creatinine is less than 2.5mg/dl, maximum dose is increased to 5-10mg BID. Patients in intervention group are evaluated for gasterointestinal side effects, skin rashs, cough and etc. If hypotension occurs, Enalapril is decreased or stopped. systolic blood pressure increased, again it is initiated. All patients receive chemotherapy according to protocol.One month later,cardiac Troponin I is measured. Then, in the terminal part of follow up, after 6-9 months, patients underwent echocardiography. Two groups are compared for change in left ventricular systolic and diastolic performance and Troponin levels. Quantitative variables in baseline and terminal part of study are calculated by paired t test in each group.Two group are compared by independent t test. All data are analyzed by SPSS software.