In cardiovascular diseases e.g. heart failure and coronary artery disease gender differences are evident in etiology, pathophysiology, clinical presentation, prognosis and response to treatment. Diabetes and hypertension are the major risk factors in women. Mechanisms leading to apparent diabetes or its clinical pre-stage are different in women and men and according to this result in different therapeutic implications. Diastolic heart failure is more frequent in women and effects and side effects of important groups of active pharmaceutical substances are, at least to some extent, different. Atrial fibrillation and ventricular arrhythmia differ in frequency of occurrence; drug induced tachycardia with QT interval prolongation is particularly frequent in women. Underlying pathomechanisms responsible for gender differences in pharmacotherapy are on the one hand differences in pharmacokinetic mechanisms. Particularly drugs which are metabolised via cytochrome P 450 CYP 3A pathway show different kinetics in women and men. In addition, important differences are evident in pharmocodynamics caused by effects of sex steroid hormones or products of X-chromosomal genes. The evidence of estrogen and testosterone receptors in cardiomyocytes and the vascular system, interaction of sex steroid hormones with cellular pathways and the role of X-chromosomal genes are the focus of basic research. Interactions of sex steroid hormone receptors with other nuclear receptors e.g. PPARs ("peroxisome proliferator-activated receptors") are another important underlying mechanism. The knowledge of different pharmacokinetic mechanisms has to be taken into consideration in pharmacotherapy of cardiovascular diseases, for example by adjustment of drug dosages in women, necessary in different groups of pharmaceutical substances or in the long run, gender differences in effects and side effects of drugs. In drug development both aspects have to be considered. There is more than one good reason to intensify basic and clinical research and research on health care on gender differences in cardiovascular diseases.