Abstract Background and Aims Chronic kidney disease and hypertension are closely related in cause and effect. As the glomerular filtration rate decreases, the frequency and severity of arterial hypertension increases. In addition, the risk of morbidity and mortality from cardiovascular diseases increases significantly with comorbidity of arterial hypertension and chronic kidney disease. The purpose of this study was to identify predictors of a decrease in GFR below 60 ml/min in patients with arterial hypertension. Method The cross-sectional study included 43 patients with arterial hypertension (average age 56.7 (10.6) years). Exclusion criteria were age over 80 years, primary kidney disease, diabetes mellitus, cancer, heart failure, stage III arterial hypertension. All patients underwent determination of cystatin C in the blood, the composition of the body was studied using the bioimpedance method and 24-hour blood pressure monitoring. To identify predictors of kidney damage, we used regression analysis with ROC curve estimation using MedCalc software. Results The optimal value (cut-off point) of the content of total adipose tissue, which allows the most accurate prediction of a decrease in GFR < 60 ml/min in patients with hypertension, was 26.1% (sensitivity −100%, specificity—77.8%), and the content of total muscle tissue—35.9% (sensitivity −100%, specificity—44.4%). The optimal value (cut-off point) of cystatin C was 1.13 (sensitivity −100%, specificity—53.9%), AUC—0.73 (0.46; 0.92). At the same time, when this predictor was included once in multiple logistic regression, the statistical significance decreased (p = 0.5). Among individual predictors of decreased renal function, indicators of 24-hour blood pressure monitoring were studied. The optimal value (cut-off point) of the ambulatory arterial stiffness index, which allows the most accurate prediction of a decrease in GFR < 60 ml/min in patients with arterial hypertension, was 0.36 (sensitivity −100%, specificity—71.4%), an indicator of an increase in the rate of increase in diastolic blood pressure. blood pressure—0.27%, AUC 0.74 (0.48; 0.91)) and the rate of increase in nighttime decrease in systolic blood pressure—8.1%, AUC 0.71 (0.47; 0.89). Conclusion Increase in total adipose tissue > 26.1%, decrease in total lean tissue <35.9%, increase in ambulatory arterial stiffness index >0.36, increase in rate of increase in diastolic blood pressure >0.27%, and increased nocturnal decrease in systolic blood pressure > 8.1% were identified as significant predictors of a decrease in GFR below 60 ml/min in hypertension.