OBJECTIVES: Cyst infections often develop as a complication in patients with autosomal dominant polycystic kidney disease (ADPKD). Although this complication has significant clinical implications, reports of cyst infection are extremely limited. Herein, we report on the status of cyst infection in patients with ADPKD to clarify this. METHODS: Among 90 patients with ADPKD admitted to our hospital from 2010 to 2017, we selected those diagnosed with cyst infection. We collected the data from medical record retrospectively. RESULTS: A total of 22 patients, comprising 12 men and 10 women, were included in the study. Infected cysts were identified on imaging in six (27.3%) patients. Bacterial culture was positive in 12 (54.5%) patients. The initial antibiotic treatment was quinolone, cephalosporin, carbapenem, and vancomycin in 7 (31.8%), 11 (50%), 3 (13.6%), and 3 (13.6%) patients, respectively. The mean hospitalization period was 12.0 days (range, 9.25–14.75), while the mean antibiotic treatment period was 26.5 days (range, 21.25–29.50). No patient died. Nine (40.9%) patients had previous episodes of cyst infection, and 11 (50.0%) had recurrence during the study period. The rate of prolonged hospitalization longer than the median of 12 days was higher in patients with maintenance dialysis, although the difference was not significant (80.0% vs. 50.0%, P = 0.1453). In multiple regression analysis, the albumin value showed a negative correlation with the hospitalization period (β-coefficient: −0.4835, 95% confidence interval: −15.5757–−0.9460, P = 0.0290). Conclusion: Patients with ADPKD who have a poor nutritional status may require additional medical attention to avoid prolonged hospitalization. (Am J Transl Med 2018. 2:146-151).