Sense of agency refers to the feeling of controlling one's own actions, and, through these actions, events in the outside world. Sense of agency is widely held to involve a retrospective inference based on matching actual effects of an action with its expected effects. We hypothesise a second, prospective aspect of sense of agency, reflecting the "fluency of action selection", based on results from subliminal priming of actions. When people responded to a target that was compatible with a preceding subliminal prime, they felt stronger sense of control over a subsequent colour effect than when the preceding prime was incompatible. Importantly, compatible and incompatible primes had the same predictive statistical relation to the colour effect. We next investigated whether differences in sense of control could be based on monitoring motor performance. By varying the timings of mask and target, we compared sense of control between a Positive Compatibility condition, where compatible primes facilitated performance, and a Negative Compatibility condition, where compatible primes impaired performance. We found that compatible priming again enhanced sense of control, irrespective of its effects on performance. We present a simple model of the prospective aspect of sense of agency, in which early signals reflecting action selection processing make a direct, experiential contribution to sense of control. Sense of agency may be partly based on an experience-based "feeling of doing", analogous to the metacognitive "feeling of knowing". (Contains 6 figures.)