Information can be declared as fundamental component for the performance of service processes.Especially for the service provision of Technical Customer Services (TCS), information is a key driver for productivity. Thereto, mobile Information Systems (IS) are a critical success factor to provide the TCS with needed information for a high-quality service delivery at the right time, at the right place and in an adequate way. Before such IS can be designed purposefully, existing information needs have to be identified first. Therefore, we investigate information needs for mobile TCS in a case study of the machinery and plant engineering industry. The resulting consolidated catalogue of information needs gives an overview of needed information of the TCS during service processes and can thus serve as a starting point for the specification of mobile TCS support systems.