Overactive bladder (OAB) is a frequent chronic disorder which impairs quality of life by frequent, uncontrollable urination. Newly developed selectiveβ 3-adrenoceptor agonists (sβ 3-agonists) have the same efficacy in treating OAB but significantly fewer side effects than the traditionally used anti-muscarinics. However, safety data on these compounds are scarce. In this study, we analysed the occurrence of adverse effects in patients taking sβ 3-agonists and their characteristics using the JADER database. The most frequently reported adverse effect associated with the use of sβ 3-agonists was urinary retention [mirabegron; crude reporting odds ratios (ROR): 62.1, 95% confidence interval (CI): 52.0-73.6, P<0.001, vibegron; crude ROR: 250, 95% CI : 134-483, P<0.001]. Data from patients with urinary retention were stratified by sex. In both men and women, the rate of urinary retention was higher when using the mirabegron/anti-muscarinic drug when compared to mirabegron monotherapy; its occurrence was higher in men with a history of benign prostatic hypertrophy than in those without. Weibull analysis showed that approximately 50% of sβ 3 agonist-induced urinary retention occurred within 15 days after initiation of treatment, and then gradually decreased. Although sβ 3-agonists are useful against OAB, they may induce several side effects, especially urinary retention, which can further evolve into more severe conditions. Urinary retention occurs more frequently in patients concomitantly taking medication that either increases urethral resistance or has organic factors that block the urethra. When using sβ 3-agonists, the concomitantly used medications and underlying diseases should be thoroughly reviewed, and safety monitoring should be instituted early during the treatment.