There are several anxiety-related reactions associated with magnetic resonance imaging (MRI). Patients who experience such reactions may disrupt the examination or move so much that images are degraded. These experiences may also influence patients' perceptions of the quality of their care. The objective of this study was to further assess the subjective experiences of patients undergoing MRI in an attempt to identify those patients likely to have problems and factors affecting their experiences. Five hundred consecutive patients undergoing MRI were surveyed using questionnaires before and immediately after imaging. Anxiety was measured using the state anxiety component of the state-trait anxiety inventory. All patients exhibited some degree of pre-imaging anxiety. This was particularly associated with a previous 'unpleasant' imaging experience. Patients who experienced problems during MRI had pre-imaging anxiety levels equivalent to patients about to undergo surgery, were more likely to react badly when first seeing the scanner and were more likely to leave the MRI unit with even greater feelings of anxiety than when they arrived. In contrast to previous studies, anxiety was not associated with either the patient's understanding of the procedure or the duration of the examination. Several features have been identified which could improve the patient's experience (e.g. better information sheet). Awareness of MRI-related anxiety should also be considered when assessing the impact of MRI on outcome for the patient.