A discussion of arbitration decisions concerning limitations on subcontracting. Topics discussed include arbitrability decisions by courts, the duty to bargain over subcontracting, NLRB deferral in subcontracting cases, and the development of arbitration standards in subcontracting disputes. The article includes a table, showing the increasing prevalence of limitations upon subcontracting found in collective bargaining agreements, and discusses arbitration decisions under each of the types of contractual limitation. The article also discusses subcontracting limitations in the public sector.