OBJECTIVE: To study the negative effects of cigarette smoke on the kidney, and to determine if those effects are reversed after smoking cessation. STUDY DESIGN: A total of 40 rats were divided into 5 groups of 8 each: group I, control group; group II, rats exposed to cigarette smoke; group III, rats that discontinued smoking for 1 month; group IV, rats that discontinued smoking for 3 months; and group V, rats that discontinued smoking for 5 months. Serum urea, creatinine, cotinine, IL-18, NGAL, and KIM-1 levels were measured in the blood samples. RESULTS: Cotinine levels in all groups were similar to those of the control group, but only the nicotine group had a significant increase. The active smoker group exposed to cigarette smoke displayed dense vacuolization. As a result of the exposure to cigarette smoke, increasing levels of urinary creatine, microalbumin, and ß-2 microglobulin and urea in serum led to changes in KIM-1 and NGAL values, which result in dysfunction of glomeruli and tubules. CONCLUSION: We observed that smoking cessation may lead to improvement after 3 months in both biochemical parameters and glomerular and tubular changes and approaches their normal values/structures 5 months later. © Science Printers and Publishers, Inc.