This study is a systematic literature review to identify data collected in the preoperative assessment. The PubMed and CINAHL databases were searched for articles published from 1997 to 2007. From the included articles, data items that were described as part of the preoperative assessment were extracted. Identified data items were categorized into 13 categories originating from SNOMED CT. Forty-one relevant articles were found. Preoperative assessment was equally performed in outpatient clinics and in-hospitals. The assessment was performed between the day of surgery and 30 days before surgery by anesthesiologists (51%) and/or nurses (39%) and/or other professionals (34%). The included articles described 541 data items. The two largest categories of data were "past history of clinical finding" and "physical examination procedure," with 212 and 75 data items. Only 6 data items "age," "diabetes," "ECG," "cardiovascular diseases," "hypertension," and "cigarette smoking and other use of tobacco" were stated in 50% or more of the articles. This study revealed a high diversity of data being collected during the preoperative assessment. Because of the diversity of patients, one undisputed preoperative assessment data set is hard to define. However, to solve the problem of data exchangeability, professionals should at least use a common core data set.