Pennine Care NHS Trust has taken an additional 1,008 sq ft on a six-year lease at No.1 Henry Square, Ask Developments' office building in St Petersfield, Ashton-under-Lyne.
The trust already occupies 28,000 sq ft. Ask completed earlier deals with national charity Shaw Trust and recruitment firm TNG at the scheme.
Adam Jackson, senior surveyor at Lambert Smith Hampton, advising Ask, said; "Despite difficult market conditions, we're pleased to see deals continuing at St Petersfield. There is interest from both the public and private sector and we are hopeful that additional space will be let in the very near future."