This review summarizes various aspects of the inherited kidney disorder nephrogenic diabetes insipidus (NDI). The clinical manifestations of the disease are presented. The important role of the genetic localization of the NDI gene to the X-chromosome long arm, in region Xq28, for carrier detection and early (prenatal) diagnosis of the disorder is emphasized. Following an overview of the cellular physiology involved in the antidiuretic action of vasopressin, possible mechanisms in the pathogenesis of NDI are discussed. We hypothesize that NDI is most probably due to the absence or abnormality of the renal V₂ receptor. This assumption is strengthened by recent findings in receptor studies, which indicate a general V₂ receptor defect in NDI, and in experiments with somatic cell hybrid cell lines, which are consistent with a co-localization of the genes for NDI and for the V2 receptor in the Xq28 region. Finally, the efficacy of the combination amiloride-hydrochlorothiazide, compared with the indomethacin-hydrochlorothiazide regimen, in the treatment of NDI is presented and the advantages of the former combination are discussed.