There have been several post mortem studies focusing on the association between liver cirrhosis and benign prostate hyperplasia; however, the results are controversial. The aim of this study was to estimate the risk of benign prostatic enlargement during a 5-year follow-up period following a liver cirrhosis diagnosis, using nationwide population-based data and a retrospective cohort design. We used the "Longitudinal Health Insurance Database," derived from the Taiwan National Health Insurance program. The study cohort comprised 661 patients who had received treatment for liver cirrhosis between 1997 and 2001; the comparison cohort was composed of 3305 randomly selected patients. Stratified Cox proportional hazard regressions were performed as a means of comparing the 5-year benign prostatic enlargement survival rate for the 2 cohorts. Of the sampled patients, 808 patients (20.4%) developed benign prostatic enlargement during the follow-up period (ie, 163 individuals from the study cohort [24.7% of the patients with liver cirrhosis] and 645 individuals from the comparison cohort [19.5% of comparison cohort patients]). The log-rank test indicated that patients with liver cirrhosis had significantly lower 5-year benign prostatic enlargement-free survival rates than the controls (P < .001). The adjusted hazard ratios for benign prostatic enlargement following diagnosis with liver cirrhosis were 1.41 during the 5-year follow-up period. We conclude that the risk for benign prostatic enlargement increased after a diagnosis of liver cirrhosis. Further studies are needed to identify the underlying pathophysiology.