The mere measurement of cognitions and in particular intentions has been shown to be sufficient to change behaviour. This study assessed the impact of measuring anticipated regret in addition to intentions and other cognitions on recorded cervical smear attendance rates following invitation in a sample of women. A total of 4,277 women received an invitation for cervical screening and information leaflet: 1,500 of whom also received a standard theory of planned behaviour questionnaire in relation to screening (TPB only group) and a further 1,500 of whom also received a TPB questionnaire plus anticipated regret questions in relation to screening (TPB plus regret group). Total recorded attendance rates indicated significantly higher attendance (ps<.05) in the two experimental groups compared to control (Control, 21%; TPB only, 26%; and TPB plus regret, 26%). However, among those returning questionnaires, there was a significantly increased attendance rate (p<.001) in the TPB plus regret group (65%) compared to the TPB only group (44%). Follow up analyses among those completing questionnaires indicated this effect to be moderated by intentions with a significant difference only apparent among strong intenders. The discussion considers the implications for understanding the 'mere measurement effect' and the use of anticipated regret to change behaviour.