In pregnancy pre-eclampsia can be complicated by the nephrotic syndrome. We report on the clinical findings in 23 patients who had the nephrotic syndrome in pregnancy with hypertension. None of these patients had any previous sign of nephropathy. In most patients clinical signs first showed up in the 3rd trimester. The prognosis for the fetus was poor. This was because of the degree of proteinuria and of uraemia (5 fetuses died). After delivery all signs cleared up, as they would have done in moderately severe pre-eclampsia. All patients were considered to be cured by six months. In spite of this the longterm prognosis is difficult to assess. It is necessary to find out whether the nephrotic syndrome was evidence of an underlying nephropathy or just was due to the pre-eclampsia. Treatment consists mainly of rest, control of hypertension, correction of low blood volume and delivery of the fetus with regard to the degree of maturity and the viability of the fetus.