The first aim of this study was to examine the differences in time judgments between meditators, who already possessed mindfulness-oriented meditation experience, and control subjects. The second was to examine the immediate effect of a long mindfulness meditation session (30 min) on the judgment of short stimulus durations (from 0.8 to 2.0 s). In addition, individual characteristics in terms of cognitive, affective (anxiety, arousal), and mindful awareness were assessed to investigate the relations between time judgments and individual states. The results showed no difference between the meditators and the controls on the different types of time judgment. The regular practice of meditation therefore did not change the judgment of passage of time or the judgment of short durations. However, the participants with a higher level of mindfulness awareness experienced a slowing down of the passage of time. In addition, the immediate effect of the mindfulness meditation session was to reduce the variability of temporal judgment in all participants. This improvement was linked, at least for the longest duration (2.0 s), to the decrease in anxiety and arousal levels as a result of the mindfulness session.