Boston Medical Center and Tufts Medical Center are raising their starting pay to $15 an hour, the highest minimum wage paid to hospital employees in Boston.

At Boston Medical Center, which serves some of the city’s poorest residents, the wage hike to $15.12 an hour will start Jan. 3, boosting pay for more than 200 housekeepers, food service workers, certified nursing assistants, and customer service representatives.

The workers are members of the Service International Employees Union Local 1199 and the American Federation of State, County and Municipal Employees, which operate under a joint contract and have more than 3,000 members at Boston Medical Center. Overall, the hospital has 6,000 employees.

Tufts Medical Center, known for its pediatric and cardiac-care services, will increase wages in waves over the next 18 months, beginning in January. The raise will affect about 225 employees among the workforce of about 5,000.

“Tufts Medical Center values the extraordinary care all our employees provide,’’ said hospital spokeswoman Brooke Hynes.

The move comes as SEIU seeks to unionize Tufts workers. The union has accused hospital officials of running an aggressive campaign to stop workers from unionizing, while hospital officials have said they were simply engaging in conversations with their employees.

The union said credit for the pay raise should go to the workers and caregivers who have been organizing at the hospital and “forced the administration’s hand.’’

At Boston Medical Center, president Kate Walsh said in a statement that the hospital had been considering raising wages for a while: “Taking this step of setting a minimum wage of $15 an hour for these workers reflects our recognition of the important role they play in making sure our patients have the best possible experience and our appreciation for all that they do for our patients and their families.’’

The current starting wage for workers at Boston Medical Center is $13 an hour. Tufts did not immediately disclose its minimum pay rate.

No other major Boston hospitals have committed to paying at least $15 an hour, according to SEIU. By comparison, the starting wage at Massachusetts General Hospital, the biggest hospital in the state (which is not unionized), is $12.63 an hour.

The raise at Boston Medical Center marks another $15-an-hour victory for Local 1199, which in June reached a deal with the Baker administration to increase starting wages to that level for more than 35,000 personal care attendants in Massachusetts. The push for $15 an hour has been sweeping the country in the past few years, with several cities, municipal employees, and New York’s fast food workers moving to a $15 starting wage.

“This is what we describe as a living wage for folks to be able to survive,’’ said Tyrek Lee, a vice president with Local 1199. “I think it’s telling for some of the richer hospitals in the state, especially in the city, that they need to follow the same trend.’’

Katie Johnston can be reached at katie.johnston@globe.com. Priyanka Dayal McCluskey can be reached at priyanka.mccluskey@globe.com.