Objectives: To investigate the quality of standardized care plans and the extent to which they are used within Swedish in-hospital somatic care. Further, to examine the quality of the knowledge summaries on which existing standardized care plans were supposed to be based. Design: Submitted documents were reviewed with study-specific protocols. Setting: A national survey, based on a structured selection of Swedish hospitals. Participants: A total of 25 Swedish hospitals participated, and were asked to submit all documents in use that were labelled standardized care plan. Results: Only 4% (34 out of 782) of the reviewed documents fulfilled the criteria for being a standardized care plan. None of the 34 knowledge summaries (an accompanying document with a compilation of scientific facts and reliable experience) was evidence-based. Conclusions: There is a lack of knowledge regarding what a standardized care plan is, and how such a document should emanate from evidence-based knowledge. Our results raise the question of how recent developments in research are used to create standardized care plans for the best possible care. In the process of developing standardized care plans it is important to acknowledge that staff who develop these plans need scientific training and experience. Standardized care plans are in the early stages of development, and at this stage it seems appropriate to initiate a discussion regarding possible cooperation at national level when developing standardized care plans for certain large groups of patients suffering from specific diseases, or undergoing the same treatment.