SummaryThe bureaucracy that the Good Clinical Practice (GCP) system generates, due to industry over-interpretation of documentation requirements, clinical monitoring, data verifications etc. is substantial. The aim of this study was to estimate the percentage cost of all such GCP-related activities within phase III clinical trials performed in Sweden in 2005. Method: An electronic questionnaire on ICH GCP-activities and their related costs was sent to 47 of the 60 member companies of the Swedish Association of the Pharmaceutical Industry (LIF). Results: The number of respondents was 29, giving a response rate of 62% and covering 97% (n 5 250) of phase III trials performed in Sweden in 2005. Approximately 50% of the total budget for a phase III study was reported to be GCP-related. 50% of the GCP-related cost was related to Source Data Verification (SDV). A vast majority (71%) of respondents did not support the notion that these GCP-related activities increase the scientific reliability of clinical trials.