Background: We aimed to characterize the population of consecutive patients undergoing coronary angiography with simultaneous renal artery angiography and assess prognostic factors at a 10 year follow-up. Methods: The KORONEF study was a prospective, single-center, observational, and descriptive study with 492 patients included. We analyzed several baseline demographics, clinical and periprocedural characteristics, and laboratory data, and we assessed the results of coronary angiography and renal artery angiography. Results: The study population consisted of 37.2% women, and the mean age was 64.4 ± 9.9 years (min. 30 years, max. 89 years). Angiography revealed significant renal artery stenosis (RAS) in 35 (7.1%) patients. Among patients with significant RAS (≥50%), we observed more women (57.1% vs. 35.7%, p = 0.011), and patients were older (69.1 ± 10.4 years vs. 64.0 ± 9.7 years, p = 0.005). In the whole population, all-cause death was reported in 29.9% of patients, myocardial infarction (MI) rate—in 11.8%, and stroke—in 4.9%. In the multivariable analysis, independent predictors of death were age 65–75 years (HR 2.88), age > 75 years (HR 8.07), diabetes (HR 1.59), previous MI (HR 1.64), chronic kidney disease (HR 2.22), unstable angina (HR 0.37), and left ventricular ejection fraction > 60% (HR 0.43). Conclusions: Over a 10 year follow-up, the all-cause death rate was 29.9%, showing no statistically significant differences between patients with and without significant RAS.