ll contributo è stato sottoposto a peer-review anonima da un revisore selezionato dalla Direzione della collana. Ricevuto il 03/03/2016; accettato il 13/06/2016; pubblicato il 14/06/2016

The essay aims to reconstruct the legal and conceptual framework occurred as a result of the repeal of the Law no.1369/1960 concerning the interposition of labor, as well as the simultaneous expansion of the joint liability of the buyer of a contract, pursued to article 29, Legislative Decree no. 276/2003. Therefore, are examined the many developments which the joint liability in contracts was submitted, extending the analysis to the rules on the health and safety of employees, the workers’ protection in the hypothesis of illegal contracts, without neglecting to analyze effects of articles 7 and 9, Law Decree no. 76/2013- which have codified the coemployment relationship in networks of company- with reference to outsourcing by contracts.