Correspondence should be sent to aguilarlleyda@gmail.com 5 6When dealing with multiple tasks, we often find ourselves in the problem of 7 establishing the order in which to tackle them. Here we show that confidence, the 8 subjective feeling in the accuracy of our decisions or actions, plays an active role in 9 task ordering. Our participants categorized perceptual stimuli along two dimensions 10 and reported the confidence on each decision, while we manipulated the difficulty 11 over each dimension independently. We found an effect of confidence in priority: 12 participants tended to address first the dimension they were more confident in. In 13 subsequent studies, we replicated this finding using task difficulty and response 14 accuracy as proxies for confidence: participants first responded to the easiest of the 15 two tasks, and their first choice was also more likely to be correct. We showed that 16this effect was not due to a difference in response availability between dimensions. 17We also extended our finding to situations of prospective confidence, and to 18 situations involving non-perceptual (mental calculation) decisions. Our results 19 support the role of confidence as a priority signal, thus strengthening the evidence 20 for confidence having an active role shaping our future behavior. 21 22It is frequent to start a day at work by compiling in a to-do list all the tasks to complete that 23 day. But once the list is written, where do we start? Which task shall we tackle first, and 24 which tasks can be postponed? Of course, this planification problem is sometimes solved by 25 taking into account external constraints, such as scheduled meetings, imminent deadlines, 26or the limited availability of specific tools or collaborators. In other circumstances, however, 27we are free to decide in which order to complete our tasks.