The purpose of this paper is to compare the three search engines Web of Science, Google Scholar and MEDLINE in regards of recovery efficiency and the overlap of relevant documents when it comes to information searching for academic purposes. Furthermore, it raises the question whether freely available search engines and licensed search engines are interchangeable with each other. The empirical data in this study were collected through searches conducted in the three search engines Web of Science, Google Scholar and MEDLINE. Twenty search queries were used and the first twenty retrieved documents for each query were examined for relevance using previously designed criteria. The documents were scored by a binary relevancy scale and thereafter a precision value for each search engine was calculated. The overlap of retrieved relevant document in all three search engines were also calculated using Jaccard’s Index. The results of this study showed that Web of Science was the search engine that had the highest precision value, 0.346 and that the largest overlap was between MEDLINE and Web of Science with a value of 0.112. / Program: Bibliotekarie