Objective To investigate the incidence rate and related clinical features of microembolic signals (MES) in patients receiving routine transcranial Doppler examinations for microembolus monitoring. Methods From July 2016 to December 2018, the patients who received routine 30-minute MES monitoring and were detected to have MES were enrolled consecutively, and their baseline data were collected. Results A total of 5 886 patients received routine 30-minute MES monitoring, and MES were detected in 50 patients, with a positive rate of 0.85%. MES of the middle cerebral artery had the highest detection rate of 84%. Among these 50 patients, 23(46%) had microemboli originating from the artery, among whom 8 had atherosclerotic cerebral or carotid artery stenosis, 10 had the involvement of intracranial arteries, 4 had moyamoya disease, 1 had and ANCA-related arteritis; 15(30%) had microemboli originating from the heart, among whom 1 had atrial fibrillation, 4 had artificial valves, and 10 had patent foramen ovale; 12(24%) had microemboli from other sources, among whom 8 had right-to-left shunt and 4 had unknown origin. The patients with MES had high incidence rates of white matter lesions (72%) and cognitive impairment (68%). Conclusions MES is relatively uncommon and may have different clinical significance and mechanisms in different diseases.