The study published by the University of Hamburg found that the number of German citizens between 18- and 64-years-old who are unable to read or write is now almost 7.5 million – or 14 percent of the work force.
Previous estimates had put the number of functionally illiterate adults in Germany at some 4 million people.
Federal Minister for Education and Research Annette Schavan was on hand as the study was presented in Berlin and said she was shocked by the findings.
“Illiteracy exists in Germany on such a scale that it shows it is no longer a niche problem,” she said. “What we need now is a national effort.”
The study by Professor Anke Grotlüschen showed that some 300,000 German citizens can't read or write at all, while another 2 million are unable to read or write more than a series of random words. A further 5.2 million are able to make out short sentences, but would fail to understand a longer text.
Sixty percent of those found to be functionally illiterate were men, and 40 percent were women. Even those who had completed a higher level of education were found to be affected, comprising 12 percent of those found to be illiterate.
To combat the problem, Schavan has launched a new initiative to promote literacy and increased education in the workplace, which will receive some €20 million until 2014. Business associations, unions, chambers and adult education centres will all take part in the programme, she said.
The study, which surveyed some 8,000 German citizens, is the country's first comprehensive examination of illiteracy in the country, the author said.
President of the KMK conference of state education ministers, Bernd Althusmann, said it was a problem that receives little notice.
“Reading and writing competence must be further developed,” he said.