The rapid development of tourist supply and demand makes Information Technologies (IT) significant, and thus, they increasingly play a more critical role in tourism marketing, distribution, promotion, and coordination. IT influences the strategic management and marketing of contemporary organisations as a paradigm-shift is experienced, transforming the best business practices globally. IT is one of the main key influences of competitiveness in the tourism/travel industry. The original purpose for adopting IT systems was simply to provide an automatic means of store and manage data (e.g. on flights and accommodation). At the same time, IT in the tourist sector enables an increased volume of transactions to be handled rapidly and effectively. This chapter presents an original customer satisfaction survey in the Greek Online Travel Agencies. For the collection of the data, a Website questionnaire was used in order to better record the customers' views on the service overall as well as their satisfaction levels on particular aspects of the service. The survey was conducted within the period September - November 2012. Final input data consists of 510 questionnaires.