BACKGROUND: The retrospective analysis of EEG signals acquired from patients under general anesthesia is crucial in understanding the patient’s unconscious brain’s state. However, the creation of such database is often tedious, cumbersome and involves human labor. Hence, we developed a Raspberry Pi-based system for archiving Electroencephalogram (EEG) signals recorded from patients under anesthesia in operating rooms (ORs) with minimal human involvement. METHODS: Using this system, we archived patient EEG signals from over 500 unique surgeries at the Emory University Orthopaedics and Spine Hospital, Atlanta, USA for around 18 months. For this, we developed a software package that runs on a Raspberry Pi and archives patient EEG signals from a SedLine(®) Root EEG Monitor (Masimo, Irvine, CA, USA) to a secure Health Insurance Portability and Accountability Act (HIPAA) compliant cloud storage. The OR number corresponding to each surgery was archived along with the EEG signal to facilitate retrospective EEG analysis. We retrospectively processed the archived EEG signals and performed signal quality checks. We also proposed a formula to compute the proportion of true EEG signal and calculated the corresponding statistics. Further, we curated and interleaved patient medical record information with the corresponding EEG signals. RESULTS: We retrospectively processed the EEG signals to demonstrate a statistically significant negative correlation between the relative alpha power (8–12Hz) of the EEG signal captured under anesthesia and the patient’s age. CONCLUSIONS: Our system is a standalone EEG archiver developed using low cost and readily available hardware. We demonstrated that one could create a large-scale EEG database with minimal human involvement. Moreover, we showed that the captured EEG signal is of good quality for retrospective analysis and combined the EEG signal with the patient medical records. This project’s software has been released under an open-source license to enable others to use and contribute.