The purpose of this Master thesis is to examine the information use and information seeking behaviour among persons who actively work with information. For this study, interviews have been conducted with a group of six persons who work with information in information intensive organizations. The aim is to answer the following questions: What kind of information is connected to the respondents’ work tasks? What is the purpose of their search for information? Which information sources do they use and what kind of information sources do they demand? The theoretical framework consists mainly of Wilsons information needs and information seeking model. The results of this study show that none of the respondents had any strategic model for their work with information. The information that the respondents were searching for is of different content and depends on the organization in which the respondent operates. There were six different purposes of the information search: to stay up to date, to prepare for work, to develop work, to plan work, to make decisions and perform work tasks. The sources of information used by the respondents were the following: library, books, databases, Internet, contact/network and different types of newspapers. The information sources that were most frequently used were contact/network, newspapers and Internet. Finally, the respondents had a demand for the following additional information sources: an extra person who could help with the work related to information, different kind of information portals and information which has been filtered and prepackaged.