The City of New York employs over 380,000 people and is the largest employer in New York City (NYC). In 2015, the City’s newly-created workplace wellness initiative, WorkWell NYC, began a pilot implementation of the National Diabetes Prevention Program (NDPP), a CDC-recognized program that aims to prevent or delay the onset of type 2 diabetes. Initially offered in-person at two NYC government agencies, the NDPP was later expanded, and an online version was offered in 2017. The New York Academy of Medicine partnered with WorkWell NYC to evaluate the effectiveness and participant experiences of the two versions. While effectiveness of the NDPP has been evaluated by many, this research contributes to the literature in its focus on worksite implementation and implementation using both in-person and online versions.