Cardiac arrhythmia is one of the most common reasons for cardiac consultation during pregnancy. Fortunately, malignant arrhythmias during the course of normal gestation are rare, and the relatively common complaint of palpitations is usually due to benign arrhythmias. However, in pregnant patients with organic heart disease, arrhythmias are often triggered by the haemodynamic burden of pregnancy and may be the first manifestation of the disease. In addition, rhythm abnormalities in patients with limited cardiac reserves may have significant haemodynamic consequences and can compromise fetal well-being. Any woman who presents with rhythm disorders during pregnancy should undergo a diagnostic evaluation to rule out an underlying disease, including cardiac, pulmonary, endocrine, or metabolic disease. Additionally, removal of precipitating factors, such as excessive ingestion of caffeine and/or alcohol, cigarette smoking, drug abuse or therapy with arrhythmogenic compounds, is indicated (as these measures are desirable in any pregnant woman). Antiarrhythmic drug therapy is indicated in such patients only in symptomatic or haemodynamically significant arrhythmias. In cases where organic heart disease or any other cause for arrhythmia is identified, the underlying disease should be treated first. Antiarrhythmic drug therapy is indicated when arrhythmias persist or as a prophylactic measure. In principle, the approach to drug therapy in pregnant patients is similar to that in non-pregnant patients. However, special consideration should be given to drug selection in order to avoid adverse effects to the fetus. Those antiarrhythmics that have been shown to be relatively safe during pregnancy include digoxin, quinidine, procainamide, some beta-blocking drugs and lignocaine (lidocaine). In addition to careful drug selection, the smallest effective dose should be used and the indication for antiarrhythmic therapy should be periodically reassessed during the course of pregnancy.