The pharmacokinetics of iopamidol 370 (Iopamiro), a non-ionic water soluble organic iodine compound, were studied in adults with different degrees of chronic renal failure and in healthy volunteers. After 50 ml were administered i.v., plasma and urine levels were determined. The main pharmacokinetic parameters were calculated on the basis of bi-compartimental open model. There were significant differences from healthy volunteers in t1/2 beta, which increased with the degree of renal failure as the clearance values decreased. t1/2 beta was equal to 1.67 h in healthy volunteers, 4.24 h in patients with mild renal failure and 10.03 h in patients with severe renal failure. The clearance decreased as follows: 0.11 (l/h kg) in healthy volunteers, 0.06 (l/h kg) in patients with mild renal failure and 0.02 (l/h kg) in patients with severe renal failure. No significant differences were found in distribution volume values nor in t1/2 alpha.