The publication of the CCO-2011 is organised into four parts. The first part summarizes the historical and conceptual framework in which occupational classifications for statistical purpose are developed, and then explains the harmonisation process. The second part presents the characteristics of the CCO-2011 and its main differences from the CCO-1994. The third part provides the complete structure of the CCO-2011, explanatory notes for the most disaggregated categories, a complete short-labeled version of the classification and finally a table of correspondences between the CCO-2011, the CCO-1994 and the CIOU-2008. The fourth part includes the decree approving the CCO-2011, and the annexes where the criteria for implementation of CCO-2011 and the methodological and terminological criteria and the references used in the Catalan translation are set out.