More than 2,600 former NATFHE members were recruited back into the ranks when their debts were written off in a six-week amnesty on subscription arrears.
A range of initiatives was now in place to tackle the decline in membership which has hit every trade union, Jean Cook, chair of membership and organisation, said.
A telephone survey of "leavers" had identified their key reasons as retirement (often early), redundancy and change of job. "We are not losing members because we are too militant, nor because we are not militant enough, nor to other trade unions. Relatively high levels of satisfaction with NATFHE were expressed by leavers."
Some problems were beyond the union's control, she said. Around 10,000 jobs had gone in FE since incorporation and up to 2,000 were likely to go this year.
But better methods of recruitment were working. As well as the amnesty, pilot mailshots to non-members had recruited 570. Keeping retired staff as members and using their expertise to recruit was also helping to boost membership.