Aortic stenosis (AS) and renal dysfunction share risk factors and often occur simultaneously. The influence of renal dysfunction on the prognosis of patients with various grades of AS has not been extensively described. The present study aimed to assess the prognostic implications of renal dysfunction in a large cohort of patients with aortic sclerosis and patients with various grades of AS. Patients diagnosed with various grades of AS by transthoracic echocardiography were assessed and divided according to renal function by estimated glomerular filtration rate (eGFR). The occurrence of all-cause mortality (primary end point) and aortic valve replacement (AVR) was noted. Of 1,178 patients (mean age 70 ± 13 years, 60% male), 327 (28%) had aortic sclerosis, 86 (7%) had mild AS, 285 (24%) had moderate AS, and 480 (41%) had severe AS. Renal dysfunction (eGFR <60 ml/min/1.73 m²) was present in 440 (37%) patients, and moderate to severe AS was observed more often in these patients compared to patients without (70 vs 62%, respectively; p = 0.008). After a median follow-up of 95 [31 to 149] months, 626 (53%) patients underwent AVR and 549 (47%) patients died. Severely impaired renal function (eGFR <30 ml/min/1.73 m²) and AVR were independently associated with all-cause mortality after correcting for AS severity. In conclusion, renal dysfunction is highly prevalent in patients with various grades of AS. After correcting for AS severity and AVR, severely impaired renal function (eGFR <30 ml/min/1.73 m²) was independently associated with all-cause mortality. Independent of renal function, AVR was associated with improved survival.