Continuous self-reported emotion expressed by four pieces of music were collected on a two-dimensional (valence and arousal) emotion space in a repeated measures (test-retest conditions) design. Initial orientation time (IOT), test-retest reliability and afterglow were examined. Median IOT was 8 seconds. Valence ratings took up to 25 (median 4), and for arousal up to 35 (median 12) seconds. Slower tempi seemed to require longer IOT. Test-retest reliability examined correlation coefficients, and compared periods of sample-by-sample good agreement in response between Test and Retest condition. About 80% of responses were reliable in both the Test and Retest conditions regardless of response dimension. Pearson correlations demonstrated better test-retest reliability for arousal responses than for valence. Retest condition ratings were within 8% of Test condition rating within participant. Average standard deviations for ratings collapsed across dimension, stimulus and conditions was 12.2% of the ratings scale range. Afterglow effects – large outliers in spread of scores just after the end of a piece – were identified. The reliability of continuous emotional response is therefore considered to be quite good, but caution must be taken as to how to deal with the opening and ending of continuous emotional response data.