Abstract Introduction and Aims Sodium bicarbonate is a commonly used drug that balances metabolic acidosis in patients with chronic kidney disease (CKD) and is said to delay disease progression. Elevated serum uric acid levels are frequently seen in CKD and the prevalence of gout disease in CKD patients is higher than in the normal population. Animal studies suggest that excessive sodium bicarbonate intake may increase uric acid levels, and in Korean Native Broilers led to visceral and articular gout. In turn, individuals with Gitelman/Bartter tubulopathy present alkemic and also show increased gout prevalence. The aim of the study was to evaluate the effect of oral sodium bicarbonate supplementation on uric acid levels after 20 weeks of treatment in patients with CKD and metabolic acidosis. Methods Patients with CKD stage 3 and 4 and HCO3- < 21mmol/l enrolled in the ongoing randomized controlled SoBic-study (since 2013) were randomized into the intervention group (target HCO3- 24±1mmol/l) or the rescue group (target HCO3- 20±1mmol/l). Baseline serum uric acid levels were determined prior to sodium bicarbonate supplementation and after 20 weeks. We used Spearman’s correlation and regression analysis to detect a possible association between the amount of sodium bicarbonate intake (milligrams per day) and the alteration of uric acid in patients using a significance level of p=0.05. Results Forty-five patients were included in the study until January 2019 (23 intervention group, 22 rescue group) and demographic data is given in table 1. Of the total patient population 24.4% were already affected by hyperuricemia (serum uric acid ≥6.5mg/dl) before participating in the study (47.8% of the intervention group, 13.6% of the rescue-group). During the study period, none of the patients showed symptoms of gout. The mean uric acid level at baseline was 7.3(±1.3) and 7.4(±1.6) after 20 weeks. The median uric acid increased by 0.1 in the intervention group (p=0.651) and decreased by 0.1 in the rescue group (p=0.889) from baseline until 20 weeks. Serum bicarbonate levels and uric acid were not correlated (rs=0.201, p=0.185). The regression analysis showed no association between the uric acid level and the total daily intake of sodium bicarbonate over 20 weeks. Conclusions In patients with CKD and metabolic acidosis the treatment with oral sodium bicarbonate for 20 weeks hat no adverse effect on the uric acid level.