The two organisations' latest annual survey of individual giving revealed donations were £7.1bn in 2003, down from £7.3bn in 2002.
A previous CAF survey of the top 500 charities revealed that the largest charities grew by 7 per cent over the same period, which suggests smaller organisations are suffering.
Average monthly donations fell from £13.89 to £12.32, according to the survey. Women gave £13.55 a month compared to men's £10.81.
Street and door-to-door collections remained the most popular mechanism, although church collections, sponsorship and legacies were the most lucrative.
But planned giving - direct debits and standing orders - is up to 16.8 per cent of total donations, from 15.3 per cent. The most popular causes remained medical research (24.4 per cent) children (21.6 per cent), religious organisations (12.6 per cent) and overseas aid (10.8 per cent).
Cathy Pharoah, CAF director of research said: "The big charities have very strong brands in an era when fundraising depends on branding and direct marketing."
NCVO chief executive Stuart Etherington said greater promotion of tax efficient giving was one way of responding to the decline.
