Renal cortical and medullary spin-lattice (T1) relaxation times were measured at various time points over a period of 56 days following the administration of a single i.p. injection of 100 mg/kg 2-bromoethanamine hydrobromide (BEA), 200 mg/kg hexachloro-1,3-butadiene (HCBD) or 100 mg/kg puromycin aminonucleoside (PAN) to male Wistar rats. Administration of a single injection of HCBD caused a dramatic, immediate rise in the cortical T1 values above control values, and these levels remained elevated until, by Day 28 postinjection the levels were back to control values. Administration of BEA also caused an elevation in cortical T1 values, but in this case these values remained above control values for the rest of the study. The administration of PAN did not produce any significant increases in cortical T1 values until 14 days postinjection. The elevated T1 values remained above control values for the rest of the study. These increases observed in cortical T1 values appeared to be mirrored by decreases in medullary T1 values. Increases in cortical T1 values were accompanied by visual changes in the NMR images and enlargement of the kidneys. The histological findings were consistent with the NMR data, confirming that morphologically the tissues did show a full recovery by Day 28 in the HCBD-treated animals. This was not the case following injection of both BEA and PAN, where necrosis was not reversible and there was no recovery of the tissues.