Conventional wisdom and studies of unconscious processing suggest that sleeping on a choice may improve decision making. Although sleep has been shown to benefit several cognitive tasks, including problem solving, its impact on everyday choices remains unclear. Here we explore the effects of ‘sleeping on it’ on preference-based decisions among multiple options. In two studies, individuals viewed several attributes describing a set of items and were asked to select their preferred item after a 12-hour interval that either contained sleep or was spent fully awake. After an overnight period including sleep, individuals showed increases in positive perceptions of the choice set. This finding contrasts with previous research showing that sleep selectively enhances recall for negative information. In addition, this increase in positive recall did not translate into a greater desire to purchase their preferred item or into an overall benefit for choice satisfaction. Time-of-day controls were used to confirm that the observed effects could not be explained by circadian influences. Thus, we show that people may feel more positive about the choice options but not more confident about the choice after ‘sleeping on’ a subjective decision. We discuss how the valence of recalled choice set information may be important in understanding the effects of sleep on multi-attribute decision making and suggest several avenues for future research.