Using mixed methods research design, the current study has analyzed Iranian researchers’ information searching behaviour on the Web.Then based on extracted concepts, the model of their information searching behavior was revealed. . Forty-four participants, including academic staff from universities and research centers were recruited for this study selected by purposive sampling. Data were gathered from questionnairs including ten questions and semi-structured interview. Each participant’s memos were analyzed using grounded theory methods adapted from Strauss & Corbin (1998). Results showed that the main objectives of subjects were doing a research, writing a paper, studying, doing assignments, downloading files and acquiring public information in using Web. The most important of learning about how to search and retrieve information were trial and error and get help from friends among the subjects. Information resources are identified by searching in information resources (e.g. search engines, references in papers, and search in Online database…) communications facilities & tools (e.g. contact with colleagues, seminars & workshops, social networking...), and information services (e.g. RSS, Alerting, and SDI). Also, Findings indicated that searching by search engines, reviewing references, searching in online databases, and contact with colleagues and studying last issue of the electronic journals were the most important for searching. The most important strategies were using search engines and scientific tools such as Google Scholar. In addition, utilizing from simple (Quick) search method was the most common among subjects. Using of topic, keywords, title of paper were most important of elements for retrieval information. Analysis of interview showed that there were nine stages in researchers’ information searching behaviour: topic selection, initiating search, formulating search query, information retrieval, access to information, information evaluation, information selection, information management, and stop/ continue.These stages located in greater four categories: search initiation behaviors, formulating search queries, search navigational behaviors, and information processing behaviors.The study contributes to the theoretical basis of Web search research. It also raises various questions within the context of user studies.