This volume contains the papers presented at CS&P 2014: 23th International Workshop on Concurrency, Specification and Programming held on September 28 - October 1, 2014 in Chemnitz. Since the early seventies Warsaw University and Humboldt-University have alternately organized an annual workshop - since 1993 as CS&P. Over time, it has grown from a bilateral seminar to a meeting attended also by colleagues from other countries than Poland and Germany. This year there are 34 participants from 10 countries. Following the workshops tradition we strive to retain an informal working atmosphere. Therefore, the proceedings includes drafts and extended abstracts as well as fully elaborated contributions.