The current paper presents the first part of Chapter 6 of the second edition of the European Guidelines for Quality Assurance in Cervical Cancer Screening. It provides guidance on how to manage women with abnormal cervical cytology. Throughout this article the Bethesda system is used for cervical cytology terminology, as the European guidelines have recommended that all systems should at least be translated into that terminology while cervical intraepithelial neoplasia (CIN) is used for histological biopsies (Cytopathology 2007; 18:213-9). A woman with a high-grade cytological lesion, a repeated low-grade lesion or with an equivocal cytology result and a positive human papillomavirus (HPV) test should be referred for colposcopy. The role of the colposcopist is to identify the source of the abnormal cells and to make an informed decision as to whether or not any treatment is required. If a patient requires treatment the colposcopist will decide which is the most appropriate method of treatment for each individual woman. The colposcopist should also organize appropriate follow-up for each woman seen. Reflex testing for high-risk HPV types of women with atypical squamous cells (ASC) of undetermined significance with referral for colposcopy of women who test positive is a first option. Repeat cytology is a second possibility. Direct referral to a gynaecologist should be restricted to special circumstances. Follow-up of low-grade squamous intraepithelial lesion is more difficult because currently there is no evidence to support any method of management as being optimal; repeat cytology and colposcopy are options, but HPV testing is not sufficiently selective, unless for older women. Women with high-grade squamous intraepithelial lesion (HSIL) or atypical squamous cells, cannot exclude HSIL (ASC-H) should be referred without triage. Women with glandular lesions require particular attention. In a subsequent issue of Cytopathology, the second part of Chapter 6 will be presented, with recommendations for management and treatment of histologically confirmed intraepithelial neoplasia and guidance for follow-up of special cases such as women who are pregnant, postmenopausal or immunocompromised.