Increasing autonomy of machine systems is a major trend in industry. It is foreseen to improve efficiency and safety of operations, but also to introduce new kinds of socio-technical challenges and risks. To address these challenges, development organizations need a set of capabilities, processes and tools to achieve the needed readiness for designing autonomous machine systems (AMS). In this study, the key challenges, design approaches and proposed solutions were studied by performing a series of semi-structured interviews with companies working in the domain of mobile machines that are in different phases of development and deployment of AMS. Based on literature and interview findings, a set of factors affecting the organizational readiness to design AMS were identified. These factors can be used within organizations to perform assessments of their capability in design-related aspects of AMS, and further to develop an evaluation framework or tool for more comprehensive organizational assessments.