INTRODUCTIONNeurosurgery is one of the youngest and rapidly evolving surgical disciplines. After adequate training, residents graduate with the capability to practice across different settings such as academic centers, community hospitals, and others. We present the effect of COVID 19 pandemic on the surgical case volume in a US training program.METHODSWe retrospectively reviewed operative case volume at our program for the year 2019 and January-mid April 2020. We chose to include the mid-March to mid-April period as it corresponded to the time when our institution started deferring elective cases. We categorized cases as an elective cranial, elective spine, and emergency (trauma and other non-elective cases). We then summarized and compared the number of cases during this period.RESULTSThe average number of cases in 2019 was 99 cases per month (37 elective cranial, 42 elective spine, and 20 emergent). In 2020, The total case number in January, February, March, and mid-March to mid-April was 97, 86, 71, and 41cases respectively. In comparison to January 2020, February, March, mid-March to mid-April showed a 12%, 27%, and 58% reduction in the number of cases. The absolute number of emergent cases was comparable in January through mid-April 2020 (17,11,15, and 16) but in mid-March to mid-April emergent cases constituted 39% of the total case number.CONCLUSIONNeurosurgical residency is an eighty-four months of rigorous training with a minimum of 800 cases is required to prepare residents for a successful career in neurosurgery. The significant decline in the number of cases due to COVID 19 might affect the quality of training, especially for senior residents.