In literature, there is not an unanimous agreement on the definition of hypertension in pregnancy. The most severe complications are pre-eclampsia and eclampsia which need an early diagnosis to be avoided. The problem of therapy is discussed: there is no evidence about the positive effect of a pharmacological treatment on the maternal and/or fetal clinical outcomes. In case of blood pressure < 180/110 mmHg, the alpha metil dopa is the first choice drug. Among calcium-antagonist drugs, the efficacy of nifedipine is proved; and in the pre-eclampsia, metil dopa, beta blockers and idralazine. Many questions are anyway still unsolved needing more studies.