Dilated cardiomyopathy is not purely a disease of the left ventricle. Right ventricular systolic and diastolic functions are impaired almost universally in children with dilated cardiomyopathy. Tissue Doppler imaging plays an essential role in evaluation of left and right ventricular functions. Aim of the work: we aimed to assess right ventricular systolic and diastolic functions in patients with dilated cardiomyopathy and to detect how much the right ventricular function impairment is correlated with the left ventricular function using tissue Doppler echocardiography. Methods: cross sectional analytical study was conducted on 30 cases with dilated cardiomyopathy their ages ranging from 2 months to 12 years with median age of 2.2 years in addition to 30 age and sex matched controls. Both cases and controls were subjected to tissue Doppler echocardiography. LV dimensions were measured from M-mode and LV systolic function was calculated. Right ventricular function was assessed by Doppler tissue S', E' and A' waves; RVMPI; TAPSE and RVFAC. Results: Right ventricular systolic and diastolic functions were significantly impaired in dilated cardiomyopathy patients. Tricuspid S', E' and TAPSE were significantly reduced (p < 0.05). Tricuspid S' and E' waves were decreased significantly with decreasing LVFS (r=0.518, r=0.481) respectively. Conclusion: right ventricular function is impaired in patients with dilated cardiomyopathy and correlated to the severity of left ventricular dysfunction.