Of its requirements: The special norm regulates like requirements for the celebration of an Administrative Contract of Servicios (CAS): Requirement realised by the usuary dependency. Existence of budgetary availability, determined by the office of budget of the organization or that does its times. In these ends the norm establishes like condition sinequanom the necessity of the service and the budgetary availability, being understood to first like the deficiency of a service different from established in its Manual of Organization and Functions in agreement with its Picture for the Assignment of personnel of the organization. Whereas second one talks about to that the budgetary consigment is necessary and availability of the resources destined to the payment of this service. It is precise to indicate that in relation to the nature of the function nonindependent matter of the CAS, has been lacked in sincerar those that are of nature permamente in relation to which they are merely temporary. An example of constitutes it to it the fact that in some sectors temporary workings have more existed nonpersonal services by than 25 years having realised which is contradictory every time the time and the continuedad toiling of it are the determining factors of permanence; in aim we hoped that this is future matter of a modifying one in order to give contractual stability to which they develop permamanentes functions. Added to this it is undeniable that the manuals of Management are called Manual of Organization and Functions; Regulation of Organization and Functions, Internal procedures of Work, Picture of Assignment of personnel and others must totally be sincerados, on the basis of the principles of specialization and meritocracy. As far as the procedure that must be followed for the materialization of service in the Regime of Contratacin Administrativa (RECAS) has settled down the following one: 2,1 Preparatory stage: Requirement includes/understands of organ or unit organic usuary, that includes the description of the service to realise and the minimum requirements and the competitions that must reunite the petitioner, as well as the description of the stages of the procedure, the justification of the hiring necessity and the budgetary availability determined by the budget office or the one that do its times of the organization..