The number on courses paid for through the pound;15 million-a-year union learning fund increased by 5,000, or 9 per cent.
The number of learning reps, who advise employees on training needs, liaise with training providers and negotiate time off for colleagues to study, has risen by 50 per cent to 12,000.
The TUC's general secretary, Brendan Barber, said: "Union learning reps are bringing thousands of people back to learning where other approaches have failed."
Eight out of 10 workers who join union courses continue in further education, the TUC says.
A "union academy" is the next step to help the TUC meet its targets of increasing the numbers of learning reps to 22,000 and helping 250,000 people into training each year. The academy is expected to operate in a similar way to the Open University.