Oregon recently launched an automatic-enrollment retirement savings program for private sector workers lacking access to other workplace retirement plans. We analyze participation choices, account balances, and inflow/outflow data using administrative records between August 2018 and April 2020. Within the small to mid-sized firms served by OregonSaves, estimated average after-tax earnings are low ($2,365 per month) and turnover rates are high (38.2 percent per year). Younger employees and employees in larger firms are less likely to opt out, but participation rates fall over time. Overall, we conclude that OregonSaves has meaningfully increased employee savings by reducing search costs.