In 185 consecutive renal recipients daily plasma K, Na, Creatinin (Cr) and 24 huv was recorded. Dialysis was done day before transplantation in all patients (pts). Pts with delayed graft function (need to dialysis) were excluded. From 185 pts 109 (58.9%)were male, 76 (41.1%) female, mean age 38.82+-12.83 years (range 12- 80). Mean of K in first and 14th day were 3.99+-0.61 and 4.02+-0.65 respectively. Hypokalemia (K<3.5) and hyperkalemia (K>5.5) were seen in 19.22% and 3.95%of pts respectively. Most of hypokalemic episodes (69.54%) occurred in second day and hyperkalemic (59.84%) episodes in 13th day. Mean of Na in first and 14th day were 131.77+-6.19 and 136.59+-4.74 respectively. Hyponatremia (Na<135) and hypernatremia (Na>145) were seen in 40.83% and 1.19% of pts respectively. There was not any severe hyponatremia (Na<125), severe hypernatremia (Na>155) and severe hyperkalemia (K>6.5), but severe hypokalemia (K<3) occurred in 6.2% of pts which mandated K supplementation. There was not any significant effect of age, sex, pre transplantation dialysis time on K and Na.conclusion: with good renal function after renal transplantation plasma K and Na variations tend to be within normal ranges.