[eng] This paper describes the basic characteristics of low cost companies (LCCs) and their expansion in Spain, one of the most popular tourist destinations in the world according to the World Tourism Organization. Using a demand perspective, the evolution of LCCs and the main implications for the tourism marked between 2000 and 2005 are analysed. The evident tendency of Low-Cost companies towards a marked growth in the number of passengers is contrasted with the evident stagnation of traditional or full service companies. The results of the analysis also show that highly significant trends related to the development of LCCs include the growing use of the Internet as an information search engine and tool for booking and paying for tourist services, the substitution of traditional holiday packages (travel and transport) for direct booking systems and a reduction in the length of stays at a destination. [Jel Classification: L83, L93]