Constraint logic programming CLP is a relatively new programming paradigm. During its 10 years of existence the theory of CLP has been increasingly understood and the two differ ent approaches domain technology and incremental linear solving have been implemented in various CLP systems. Meanwhile the commercial attractivity of CLP has been growing. Since 1989 a couple of commercial CLP systems appeared on the software market and have been successfully used in many real life applications. The power of CLP stems from its ability to solve hard combinatorial problems such as planning scheduling resource allocation and many others. How CLP originated from two declarative paradigms - constraint solving and logic programming - is informally explained and the relationship between the different ap proaches in CLP is presented. The main part of the article presents a real life scheduling appli cation for the largest Slovak metallurgy company using the CLP system ECL PS.