The European Organisation for Research and Treatment of Cancer (EORTC) has a portfolio of questionnaire modules to supplement the QLQ-C30 to assess patient reported outcomes in cancer clinical trials. This study updated the module for colorectal cancer. A review of the literature identified 20 articles that used the EORTC colorectal module. Eight papers did not report data from scales addressing sexual function and 8 added additional scales to assess ano-rectal function. Interviews with patients (n=79) and professionals (n=11) informed item selection, reduction and modification. A new 29 item module was devised and further patient interviews (n=120) examined its format and content validity. Patients found the new module acceptable with relevant content. The new module, the EORTC QLQ-CR29, is hypothesised as containing 6 scales and 11 single items. An international study examining its clinical and psychometric validity will be performed.