Maintenance is one area of business that recently has been considered as an activity contributing efficiently to the companies' strategic goals. Understanding the way maintenance could utilise modern technology such as computerised tools or digital data processing is one way to make maintenance profitable. Current research lack appropriate methods for determining data and IT requirements, as well as understanding the way IT could be utilised for enhancing maintenance profitability. This thesis studies and develops tools, methods and theories of how information technology can be utilised for maintenance management in order to reach profitable maintenance. The main research problem is therefore: What are the demands on information technology systems to achieve profitable maintenance? The main problem has been divided into three research questions: RQ1) What are the demands on data and information technology systems for strategic management of maintenance?, RQ2) How can we identify relevant data and information technology systems required to achieve cost-effective maintenance decisions? and RQ3) How can we describe the utilisation of information technology within maintenance? This thesis is based on a systems theory approach, where maintenance is not seen as an isolated activity, but something that interacts, affects and is affected by several other activities, such as production, logistic and quality. Several methods have been used for answering the research questions, but the theory-testing case study method dominates. Main results achieved in the thesis are models and theory for 1) creating a relevant set of data for cost-effective mainte-nance decisions, 2) monitoring the performance of maintenance, suggest invest-ment possibilities and show maintenance contribution on company strategic level, 3) identifying IT systems requirements demanded to achieve profitable maintenance and 4) assessing the IT maturity of a maintenance organisation for the effective utilisation of IT systems. As an illustrative example of computerised maintenance management demands a conceptual decision support model has been developed, which aims at filling the gaps of poor IT coverage for strategic maintenance decision-making. This thesis concludes that the demands of data and IT applications must be connected to the overall maintenance demands, which are reflected in the maintenance goals, purposes and strategy, in order to achieve profitable maintenance. Furthermore, structured methods that ensure the connection between maintenance business goals and data or IT demands are of importance. The ability to make use if IT within maintenance is reflected in the relative IT maturity of the maintenance organisation. Being able to define the IT maturity allows for choosing the most appropriate IT tool to invest in, so that current and future needs of IT support are also covered for with maximum benefit and minimum cost.