Objective In this article we report on the use of the IOSN as a referral tool in primary care and the need for sedation in the referred patient population (as determined by the IOSN score).Setting Four centres in the North West of England (primary care) accepting referrals for treatment with the aid of sedation participated in this study.Design A service evaluation.Subjects (materials) and methods The four were provided with IOSN referral forms, operator and patient questionnaires. The centres distributed IOSN forms to referrers as a means of recommending patients for sedation. All patients receiving treatment under sedation (having been referred for treatment through the IOSN form) were asked to complete the patient questionnaire. The individual operator who undertook the treatment under sedation was asked to complete the operator questionnaire. Data were entered into SPSS and the IOSN score noted. Statistical analyses of the data utilised descriptives and comparisons between groups using the Chi Squared test.Results Seventy-eight percent of the patients (n = 140) in this study were receiving treatment with sedation appropriately according to the principals of the IOSN. Patients deemed by the IOSN tool to have a low need for sedation were less likely to cancel their appointment if sedation had not been given. The majority of patients were female (70%) and the majority of operators and patients reported the IOSN forms acceptable for use.Conclusions This study provides support for using the IOSN as a tool for organising sedation referral. The majority of operators and patients reported the IOSN forms acceptable for use. © 2012 Macmillan Publishers Limited. All rights reserved.