James M. Boles, who has served as president and CEO of People Inc. since 1981, will retire from the nonprofit human-services agency this fall and be replaced by Rhonda Frederick, the chief operating officer, People Inc.’s board of directors announced this morning.

During his 33 years in the top leadership position, Boles saw People Inc. grow from 200 employees and a $2 million annual budget to more than 3,200 employees and a $144 million budget today. The agency serves more than 12,000 people with special needs in the area.

Frederick began working for People Inc. in 1980 as a direct care staff member. She has a bachelor’s degree in social work from Rochester Institute of Technology and a master’s degree in public administration from Canisius College.

Frederick has served as People Inc.’s chief operating officer since 2002, and in recent years took on increasing responsibilities overseeing most of the agency’s budget and work force in preparation for succeeding Boles. She will take over as president and CEO on Oct. 1.

“Because of Dr. Boles’ strategic direction, we anticipate a very seamless transition in our CEO position. We will continue in that direction as we strengthen and enhance our services as the largest human-services agency in the region with a special focus on quality improvement, staff support and continued expansion into health-care services,” Mary Ann Kedron, the board’s chairwoman, said in a statement.