Objectives: to identify fast and slow spindle cortical generators through Electrical Source Imaging (ESI), recording data with a 256-channel EEG; Design: subjects underwent a day-time nap while EEG was acquired; analysis was performed off line; Setting: recordings were performed in an electrically shielded, sound proof, darkened laboratory room; Patients or Participants: 11 healthy subjects with no neurological nor sleep disturbance, not taking drugs; Interventions: N/A; Measurements and Results: spindles were visually scored by an experienced neurologist; EEG traces were independently bandpass fitered at 10-12 Hz for slow and at 12-14 Hz for fast spindles. EEG was segmented on the marker position, and segments separately averaged. and independently. Cortical sources were localized using the low-resolution brain electromagnetic tomography analysis (LORETA) on the Montreal Neurological Institute (MNI) brain. Maximal intensities were compared through the Wilcoxon matched pairs test (p<0.05). Five traces were discarded, either beacause lacking sleep or due to excessive artifatcs. EEG recordings included in the analysispresented a mean of 41 spindles per participant (24 slow and 17 fast). Two to three slow spindles' generators were identified in the frontal lobe in all cases, with an additional source in precuneus and inferior parietal gyrus in two cases. Fast spindles had multiple sources identified purely in the frontal cortex in half of the cases, with other cases localizing frontal and temporal, or temporal and parietal. Source intensities were overall comparable (p= 0.44). Conclusions: our results demonstrate multiple, synchronous and equipotent spindles' cortical generators in healthy subjects, supporting the hypothesis of local sleep phenomena.