Organisations face serious challenges in optimising their channel mix. The research question of how to design a multi-channel mix is broken down into a 'what' (content) and a 'how' (process) question: What are the strengths and weaknesses per channel throughout the sales cycle, and how can they be used in a channel mix? What are the characteristics of multi-channel design processes, and which demands do they place on design support methods? Combined use of the web, call centres, retail stores and personal sales in multiple cases were studied. Regarding design content, several significant differences among the support these channels can provide were found. Regarding design processes, ill-structured and solution driven processes were observed. Some of the design process challenges are as follows: speed, team communication, customer centricity, focused decision-making and implementation, and maintaining cohesion across channels, stakeholder interests and design.