The as yet unnamed combined firm will be headed by FHD's Adrian Day as MD and Pauffley's Patrick Eastwood as deputy MD.
Fishburn Hedges group CEO Neil Hedges said: 'The world of business communications is changing fast and entering a bold, new interactive age.
'The combination of Pauffley and FHD provides us with the perfect platform from which to invest for this exciting future.'
The firm will concentrate on its digital offering. It will be based within Fishburn Hed-ges' offices in central London.
Pauffley specialises in helping companies tailor corporate literature for key stakeholders, including investors, employees, shareholders and local communities.
Projects include annual reports, CSR reports, corporate brochures, employee engagement programmes, codes of conduct, brands and visual identities and websites.