Subjective feeling, defined as the conscious experience of emotion and measured by self-report, is generally used as a manipulation check in studying emotional processes, rather than being the primary focus of research. In this paper, we report a first investigation into the processes involved in the emergence of a subjective feeling. We hypothesized that the oscillatory brain activity presumed to underlie the emergence of a subjective feeling can be measured by electroencephalographic (EEG) frequency band activity, similar to what has been shown in the literature for the conscious representation of objects. Emotional reactions were induced in participants using static visual stimuli. Episodes for which participants reported a subjective feeling were compared to those that did not lead to a conscious emotional experience, in order to identify potential differences between these two kinds of reactions at the oscillatory level. Discrete wavelet transforms of the EEG signal in gamma (31–63 Hz) and beta (15–31 Hz) bands showed significant differences between these two types of reactions. In addition, whereas beta band activities were widely distributed, differences in gamma band activity were predominantly observed in the frontal and prefrontal regions. The results are interpreted and discussed in terms of the complexity of the processes required to perform the affective monitoring task. It is suggested that future work on coherent mental representation of multimodal reaction patterns leading to the emergence of conscious emotional experience should include modifications in the time window examined and an extension of the frequency range to be considered.