Prescribing opioids for chronic noncancer pain has been strictly regulated for two decades in Taiwan. The aim of this study was to survey the patients' perspectives and potential drawbacks following long-term use of opioids. Methods: An observational cross-sectional survey using the Taiwanese version of Brief Pain Inventory was conducted among outpatients with chronic noncancer pain registered by the Taiwan Food and Drug Administration. Patients were also asked about their sexual behavior, depression, opioid misuse behaviors, and use of complementary and alternative medicine. Results: For 210 of 328 outpatients (64.0%), the median pain duration was 96 months and opioid treatment duration was 57 months. The median morphine equivalent dose was 150 mg/d, with 30.5% of patients exceeding the daily watchful dose, defined as 200 mg of morphine equivalent dose. Pain reduction after taking opioids was ∼50% in the past week. The top three diagnoses were chronic pancreatitis, spinal cord injury, and neuralgia. The leading side effects were constipation (46.7%), and decreased sexual desire (69.5%) and satisfaction (57.9%). Depression was currently diagnosed in 55.2% of patients. Twenty patients (9.5%) displayed at least one aberrant behavior in the past month. Only 76 (36.2%) patients had ever received nerve block procedures, and 118 (56.2%) tried complementary and alternative medicine. Conclusion: This nationwide survey described the concurrent pain intensity, daily function, and various adverse effects by long-term opioids among 210 monitored outpatients with chronic noncancer pain in Taiwan. More efforts are suggested to reduce opioid prescriptions in the 30% of patients exceeding daily watchful dose.