Delayed double-J ureteric stent (DJ) removal may cause severe morbidity. We aimed to identify high-risk patients for forgotten DJs to prevent iatrogenic injury and improve safety. Data of patients with DJs placed after ureterorenoscopic lithotripsy (URSL) between 2000 and 2013 from the National Health Insurance Database in Taiwan were included. Forgotten DJs were defined as indwelling DJs for > 6 months after URSL, which is approximately two times longer than the expiratory duration. Age at stenting, sex, socioeconomic status, specialty of stenting physician, comorbidities, postoperative emergency room visiting and abdominal plain x-ray filming frequencies, and alpha blocker use for > 7 days after stenting were analysed. Of 13,058 patients, 12,969 (99.31%) had timely removed DJs while 89 (0.68%) had forgotten DJs. Per a univariate analysis, patients with forgotten DJs were older, female, and of low socioeconomic status, and the use of more than one DJ for one URSL, placement by non-urologists, and less frequent postoperative abdominal plain x-ray filming and postoperative alpha blocker use were risk factors. Per a multivariate analysis, elderly patients (Odds ratio [OR] = 3.37, 95% confidence interval (CI) 1.36-8.32, p = 0.0085), DJ placement by non-urologists (OR = 9.63, 95% CI 6.09-15.24, p < 0.0001), more than two DJs for one URSL (OR = 2.93, 95% CI 1.58-5.42, p = 0.0006), and less frequent postoperative abdominal plain x-ray filming (OR = 0.66, 95% CI 0.51-0.86, p = 0.0016) were significantly associated with forgotten DJs. Forgotten URSL-related DJs are infrequent in Taiwan. Old age, complicated DJ insertion requiring more than two stents for one URSL, and stent placement by non-urologists are risk factors. Physicians should be aware of these high-risk patients.