In this review we aim to give a comprehensive overview over the current knowledge of the cellular control of renin release. We hereby focus on the inhibitory effects of calcium on the exocytosis of renin. After a short introduction into general aspects of the regulation of renin release, including a brief summary on the role of the second messengers cAMP and cGMP, we will discuss parts of the literature on the effects of calcium on the renin system together with recent studies from our laboratory, investigating putative calcium influx and extrusion pathways of juxtaglomerular cells. Finally, as the precise mechanisms by which calcium inhibits the exocytosis of renin are far from being understood, we will present some hypotheses on the intracellular events being involved in the suppression of renin release by calcium.