Three types of calcium channels have been identified voltage-sensitive, receptor operated (cardiac muscle and vascularsmooth muscle) and stretch operated (in some blood vessels) channels. Using electrophysiological and pharmacologicaltechniques, three different types of voltage-gated calcium channels have been identified, namely, L-type (for long lasting,large channels), T–type (for transient, tiny channels) and N–type (for neuronal, neither L nor T). Many compounds are knownto have a calcium channel inhibitory effect. Calcium antagonists, based on the specificity of inhibition of the slow calciumcurrent, can be classified into three groups: Group A: for 90 to 100 percent inhibition of calcium influx without change in thesodium current (verapamil, diltiazem and the dihydropyridines); Group B: for 50 to 70 percent inhibition of calcium influxcurrent without change in the sodium current (bepridil, cinnarizine and prenylamine) and Group C: for agents exhibitingsome inhibition of calcium influx (phenytoin, indomethacin and propranolol). There is now increasing evidence that, certaincalcium channel blockers especially the dihydropyridines are more strongly associated with vasodilation of afferent arteriolesthan of efferent arterioles and also with increase intraglomerular pressure and albuminuria. Thus they have a beneficial effectin terms of reducing proteinuria and slowing the progression of diabetic renal failure