This book constitutes the proceedings of the 8th International Computer Science Symposium in Russia, CSR 2013, held in Ekaterinburg, Russia, in June 2013. The 29 full papers presented in this volume were carefully reviewed and selected from 52 submissions. In addition the book contains 8 invited lectures. The papers are organized in topical sections on: algorithms; automata; logic and proof complexity; complexity; words and languages; and logic and automata.