Academic search e ngines, intends to run through the current panorama of the academic search engines through a quantitative approach that analyses the reliability and consistence of these services. The objective is to describe the main characteristics of these engines, to highlight their advantages and drawbacks, and to discuss the implications of these new products in the future of scientific communication and their impact on the research measurement and evaluation. In short, Academic search engines presents a summary view of the new challenges that the Web set to the scientific activity through the most novel and innovative searching services available on the web.