There is little agreement on the most effective and safest treatment for feline demodicosis. Protocols generally consist of long‐lasting therapy courses based on rinses, subcutaneous injections, oral drug administration or repeated spot‐on formulation and the efficacy of most of these is poorly documented. Many of these products have also been associated with adverse effects and may be difficult to administer in cats, leading to poor owner compliance and treatment failure. This case report describes the successful use of fluralaner in treating a generalised form of demodicosis caused by Demodex cati in an adult cat that was probably triggered by chronic glucocorticoid administration. After a single oral dose of 28 mg/kg fluralaner, negative skin scrapings were obtained within one month and clinical cure within two months. No side effects were observed. Larger studies are needed to evaluate the efficacy of fluralaner in treating feline generalised demodicosis.