At least 94 percent of participants are happy with the program, the The Kaiser Family Foundation survey found.
The survey of more than 1,000 participants found that 63 percent were "very satisfied" with the program; another 31 percent said they were "somewhat satisfied."
The plan's goal is to provide health care for residents who lack private insurance but are not eligible for other public programs.
More than 45,000 residents are enrolled in the city-run program, which began in 2007. The program covers uninsured residents regardless of pre-existing conditions, employment status or immigration status.
The program has been able to cover about 75 percent of the participants for about $120 million a year, including city funds and state grants.
In the survey, 92 percent of enrollees said they signed up for the program because they could not afford medical care or health insurance.