Help the Aged and Age Concern England have agreed in principle to form a single charity serving older people in the UK and abroad.
Both boards of trustees have backed the move and they will now consult with partner bodies.
Catherine McLoughlin, chair of Age Concern England, said: "Spending time and energy operating separately no longer makes sense. Instead, we intend to pool our talents and resources to ensure older people’s needs receive the even greater focus they deserve."
She cited social care as a key area illustrating the need for "the strongest possible advocate for older people's rights and dignity".
Help the Aged chair Jo Connell said: "The demands of an ageing society mean that this in-principle decision – which has been taken collaboratively and in partnership – is the right one for older people today and tomorrow."
Consultation will cover the 353 local Age Concern bodies around the country, the independent Age Concerns in Scotland, Wales and Northern Ireland and Help Age International, an international charity with a longstanding partnership with Help the Aged.
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