Background: Generalized demodicosis in dogs can be challenging to manage, especially in adult-onset cases., Hypothesis/objectives: This study evaluated the efficacy of oral fluralaner at the dose of 25-50 mg/kg for the treatment of canine generalized demodicosis., Animals: Client-owned dogs from Bangkok, Thailand, diagnosed with generalized demodicosis according to published criteria., Methods: Deep skin scrapings were performed at three to five affected areas to evaluate numbers of mites. Repeat examinations were performed monthly until parasitological cure; dogs were then followed up for two to 12 months. Parasitological cure was defined as two negative skin scrapings achieved one month apart., Results: One hundred and fifteen dogs were included in the study, 73 with adult-onset demodicosis and 42 with juvenile-onset demodicosis. Twenty one dogs were lost to follow-up and 27 had one negative skin scraping but did not return. Sixty seven dogs (21 with juvenile-onset and 46 with adult-onset disease) reached parasitological cure, which occurred after two, three and four months in 63%, 85% and 100% (respectively) of dogs with adult-onset demodicosis, cumulatively, and after two and three months in 81% and 100% of dogs with juvenile-onset demodicosis. Underlying causes associated with adult-onset demodicosis included atopic dermatitis, neoplasia, metabolic diseases and idiopathy. No adverse effects of fluralaner were observed in any of the dogs., Conclusion: Fluralaner given at the label dose for flea and tick prevention is effective for the treatment of canine generalized demodicosis., (© 2018 ESVD and ACVD.)