BACKGROUND AND AIM: Since 2017 electric kick scooters (E-Scoters) have been expanded across cities around the globe. E-Scooter share systems provide a micro-mobility solution in urban areas. To our knowledge, no previous studies have quantified the health risks and benefits of E-Scooters. METHODS: This study followed a quantitative health impact assessment approach, to estimate the risks and benefits of e-scooter sharing systems. Specifically, we quantified the health impacts related to three exposures: physical activity, air pollution, and traffic incidents. We analyzed E-scooter systems, in Atlanta, Georgia, and Portland, Oregon. Input data on transport, traffic safety, air quality, and physical activity were collated from public records and scientific publications. We modeled the health impacts on adult users related to mortality, disease incidence, disability-adjusted life years, and health economic impacts (related to morbidity and mortality). RESULTS:In Atlanta,15,792 E-scooter trips were made each day. From those 42% substituted car trips, 48% walk trips, 4% bike trips, and 2% transit trips. Among all travelers, we estimated an increment of 3.4 million USD in health economic impacts of E-Scooters, mainly derived by the increment in traffic injuries. In Portland, 4,885 E-scooter trips were made each day, with a similar mode shift than in Atlanta. Among Portland travelers, we estimated a reduction of 1.5 million USD in health economic impacts of E-Scooters, mainly derived from the reduction in traffic fatalities. When we disaggregate the analysis by mode of transport, the substitution of public transit, bike or walk trips by E-Scooter resulted in more health risks, and the substitution of car trips by E-Scooter resulted as a health benefit. CONCLUSIONS:E-scooters implementation will benefit from a health lens. Depending on the modal shift, and the traffic safety measures implemented around E-Scooters, this micro-mobility solution could be a health risk or benefit. This study supports the E-scooter implementation that prioritizes car trip substitution. KEYWORDS: Transport, E-Scooter, Urban health, Health Impact Assessment, Traffic incidents, Air Pollution