Worldwide, guidelines support the routine use of anaesthetic preoperative assessment (POA), a process that is frequently supported by pro formas and unvalidated questionnaires. Electronic questionnaires can provide reliable data. A local initiative has seen the development of a computerised electronic Personal Assessment Questionnaire (ePAQ).To develop and validate a novel electronic instrument for POA.The content and face validity were evaluated in 30 patients. The questionnaire was then modified and completed by a further 300 patients, evaluating the reliability of its items and scoring algorithms for BMI and American Society of Anesthesiologists (ASA) physical status. The study was approved by the South Yorkshire Regional Ethics Committee (REC 09/H1308/127).The study was conducted in a tertiary teaching hospital in the United Kingdom between January 2011 and February 2012 and was funded by a research grant from the Charitable Trustees of Sheffield Teaching Hospitals National Health Service Foundation Trust.A total of 330 patients aged 18 years or older, listed for surgery and able to read and understand English, were recruited. Neurosurgery; ear, nose and throat; orthopaedics; gynaecology; general and plastic surgery; ophthalmology and urology patients were included. All participants provided written consent.Validation including test-retest analysis, assessment of patient value and burden, assessment of accuracy, mean score difference of BMI estimation and comparison of inter-rater ASA grading.In all, 77% of patients reported that the ePAQ helped with communication, 99% that it was easy to complete and 98% that they would be happy to use it again. ePAQ preoperative assigned ASA grades matched consultant-assigned grades more frequently than nurse-assigned grades. Self-reported BMI classification was correct in 78% of patients and within one WHO category in a further 21%. Test-retest scores were good.Initial evaluation suggests that ePAQ is acceptable to patients. Data collected using the system were found to be reliable, and its intrinsic scoring systems for ASA and BMI are comparable with values assigned by clinicians.