Healthy subjects and subjects with mild and moderate hepatic impairment are admitted on Day 1. Subjects receive a single oral dose of Mirabegron in the morning of Day 1 and will remain in the unit till Day 5 with outpatient visits on Days 6 and 7 for healthy subjects and Days 6, 7, 9 and 11 for subjects with hepatic impairment. Blood sampling for PK assessment will be up to 144 hrs post dose for healthy subjects and up to 240 hrs post dose for subjects with hepatic impairment. An additional blood sample was obtained for all subjects 4 hrs post dose for protein binding.