Article 35 of the Spanish Constitution proclaims the right to work, which is the right to job security and therefore permanent contracts. For the temporary contract the employer has to certify that cause. The temporary, regulated in Article 15 of the Statute of Workers, the regulations developed by Royal Decree 2720/1998, is limited to fixed-term scenarios that meet an objective need and the business cycle of the company, the job is his object must be limited in time, requiring a strict correspondence between the timing and nature of work. The normative basis of temporary contracts and establishes the “causality” as a determinant for the legal origin of the contracts awarded for limited duration or temporary, is precisely the gulf between formal cause and the facts relied on characterizing its really what sets the existence of Fraud Act. Be presumed to be indefinite-term contracts entered into in fraud of law. In case of temporary contracts concatenated, sufficient that only one of them has been held in circumvention of the law-though not the last, so that the worker acquires the fixed condition, without being necessary that the worker exceeds the legal maximum time provided for temporary contracts, which in this case, would also become undefined. Eventual contracts “for reasons of production to meet the situational demands of the market, work or excess accumulation of orders”. They are used to cover peak demand with a purely circumstantial. Comes a year and no one knows if they’ll happen, because if they occur cyclically the worker shall have a fixed contract discontinuous. The employment contract must justify their cause and apply a temporary, legal burden of proof borne by the employer, who must prove two things: the cause and temporality. The employer must flee vague expressions in the contract of employment such as orders increase season, given that peak increases in orders are produced and this alone does not justify that, exceptionally, the employer required increased hiring at the moment determined but the place every year on the same dates. In general, if we study the recruitment potential of a company will see that every year at its peak potential hires are made, and probably were intended for the increase of work is every year in the season. Not only hostelry in the Balearic Islands this affects the timing, many businesses, especially in commerce and Nautica are affecting the seasonality and the hospitality at the figure of the batch should be fixed, after that of fixed Figure contract more widespread in the Islands. Given this situation, if the employer does not apply the law of contract by discontinuous fixed contracts and temporary contract employee challenges her, the worker will become indefinite. However it is noteworthy that the legal claims to the large number of fixed-term contracts are formalized in Spain – over 14 million a year, have not been too many proportionally. Paula Vidal Mayrata