In recent years, substantial investigative attention has focused on therapeutic regimens that could retard the progression of chronic renal insufficiency. Emphasis has been placed on the effects of antihypertensive treatment on renal hemodynamics and preservation of renal function. It has been suggested that some classes of antihypertensive agents may confer a greater renoprotective effect, especially agents that lower glomerular capillary pressure. Conversely, by virtue of their ability to preferentially dilate the afferent arteriole calcium antagonists theoretically could favor an increase in glomerular capillary pressure thereby accelerating the decline of renal function. In this review we survey the literature critically and conclude that in patients with essential hypertension and in patients with chronic renal insufficiency, calcium antagonists effectively reduce systemic blood pressure while maintaining glomerular filtration rate and effective renal plasma flow. Preliminary results from a few long-term studies suggest that calcium antagonists may even attenuate the decline in renal function of patients with chronic renal failure. The majority of studies in humans, however, have been nonrandomized, of too short duration, or confounded by investigative difficulties precluding definite conclusions whether calcium antagonists have renoprotective effects. Although the possibility that calcium antagonists may retard progression of renal disease remains to be ascertained, the available evidence indicates that calcium antagonists may be used in patients with renal functional impairment without further exacerbating renal function.