The study among staff in technology colleges - some of the best equipped schools in the country - shows the scale of the Government's task in "wiring up" British education.
The Prime Minister has pledged that by 2002 every school will be connected to the Internet and equipped to exploit the information revolution.
But the biggest task by far, the survey shows, will be to train teachers to make the most of information and communications technology.
From September, for the first time, all initial teacher training will be required to cover information technology. Some pounds 230m from the National Lottery fund will be spent over the next three years training existing teachers.
And in the coming year pounds 100m will develop the National Grid for Learning, including computer programmes and back-up material for schools.
The Technology Colleges Trust found in a survey of nearly 7,000 teachers that fewer than one in five had "sufficient confidence and competence in the use of IT applications to enable them to apply and practise them or to develop IT capability in pupils".
Aspects of IT which left the majority of teachers baffled included the use of the Internet, e-mails, CD-Roms, computer graphics and desk top publishing.
Commenting on the survey, Eve Gillmon, TCT's development director, said that there are approximately 450,000 serving teachers whose training did not include IT.