Background and Purpose: Despite the successful use of a ketogenic diet in pediatric epilepsy, its application in adults has been limited.The aim of this meta-analysis was to summarize the findings of relevant published studies in order to identify the efficacy of and compliance with a ketogenic diet and its main subtypes (i.e.,classic ketogenic diet and modified Atkins diet) in adults with intractable epilepsy,and to provide useful information for clinical practice.Methods:Electronic searches of PubMed, EMBASE, Google Scholar, and the ISI Web of Science were conducted to identify studies of the efficacy of and patient compliance with a ketogenic diet in adults with intractable epilepsy; the included studies were reviewed.Meta-analyses were performed using STATA to determine combined efficacy rates and combined rates of compliance with the ketogenic diet and its main subtypes.Results: In total, 12 studies qualified for inclusion, and data from 270 patients were evaluated.The results of the meta-analysis revealed combined efficacy rates of all types of ketogenic diet, a classical ketogenic diet, and a modified Atkins diet were 42%, 52%,and 34%, respectively; the corresponding combined compliance rates were 45%, 38%, and 56%.Conclusions:The results indicate that a ketogenic diet is a promising complementary therapy in adult intractable epilepsy, and that while a classical ketogenic diet may be more effective, adult patients are likely to be less compliant with it than with a modified Atkins diet.