The International Classification of Functioning, Disability and Health holds great promise for providing rehabilitation disciplines including physiotherapy, with a universal language. The aim of this study was to investigate the content validity of the International Classification of Functioning, Disability and Health intervention categories for physiotherapists treating patients with musculoskeletal conditions. The study was conducted as a retrospective cross-sectional multicenter study in Switzerland. It was performed with convenience samples of 300 clinical records of patients with musculoskeletal conditions. This study recommends three checklists with 38 second-level intervention categories for acute, 46 for rehabilitation, and 38 for the long-term context. The practical application of three lists, each containing second level intervention categories, should improve the standardization of documentation in physiotherapy practice. This may also provide the transparency increasingly demanded in the current political climate.