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3 5 that enable these complex organisms to regenerate their entire body, including the brain. 3 6 Classical data suggest that they may also be capable of long-term memory. Thus, the planarian 3 7 system may offer the unique opportunity to study brain regeneration and memory in the same 3 8 animal. To establish a system for the investigation of the dynamics of memory in a regenerating 3 9 brain, we developed a computerized training and testing paradigm that avoided the many issues 4 0 that confounded previous, manual attempts to train planaria. We then used this new system to 4 1 train flatworms in an environmental familiarization protocol. We show that worms exhibit 4 2 environmental familiarization, and that this memory persists for at least 14 days – long enough 4 3 for the brain to regenerate. We further show that trained, decapitated planaria exhibit evidence 4 4 of memory retrieval in a savings paradigm after regenerating a new head. Our work establishes 4 5 a foundation for objective, high-throughput assays in this molecularly-tractable model system 4 6 that will shed light on the fundamental interface between body patterning and stored memories. 4 7 We propose planaria as a key emerging model species for mechanistic investigations of the