This book constitutes the proceedings of the 25th International Conference on Automated Deduction, CADE-25, held in Berlin, Germany, in August 2015.The 36 revised full papers presented ( 24 full papers and 12 system descriptions) were carefully reviewed and selected from 85 submissions. CADE is the major forum for the presentation of research in all aspects of automated deduction, including foundations, applications, implementations and practical experience.