Gestational trophoblastic disease is characterized by abnormal proliferation of pregnancy-associated trophoblastic tissue with malignant potential. Gestational trophoblastic disease covers a spectrum of conditions including hydatidiform mole, invasive mole, choriocarcinoma and placental site trophoblastic tumour. It is very important to understand the pathophysiology and natural history of the disease in order to achieve faster recognition and effective treatment. The presence and course of the disease can be monitored with quantitative levels of human chorionic gonadotrophin in all cases. Clinical signs and symptoms are usually insufficient to diagnose and predict the extent of disease. Nowadays, gestational trophoblastic diseases are the best treated gynaecological malignancy thanks to modern technology. This review covers various aspects of gestational trophoblastic disease: its development, epidemiology, aetiology and pathogenesis, as well as its classification, clinical manifestations and diagnostic methods.