This book constitutes the refereed proceedings of the 40th International Conference on Current Trends in Theory and Practice of Computer Science, SOFSEM 2014, held in Novy Smokovec, Slovakia, in January 2014. The 40 revised full papers presented in this volume were carefully reviewed and selected from 104 submissions. The book also contains 6 invited talks. The contributions covers topics as: Foundations of Computer Science, Software and Web Engineering, as well as Data, Information and Knowledge Engineering and Cryptography, Security and Verification.