A sixth of workers have lost track of a company pension fund after moving jobs and the vast majority have no idea how much their contributions amount to, Prudential research has found.
The poll of 2,000 workers revealed 76% do not know how much their pension pots are worth.
It also found 81% of workers do not bother to transfer their previous company pensions across to their new employer, while 15% relied on their new bosses to do it.
The insurer said the results were an indication the number of lost pension pots would increase.
Stan Russell, retirement expert at Prudential, said: "Saving into a pension today is an important step in the right direction for workers, to help ensure a comfortable retirement."
He added it was essential people understand the amount of retirement saving their have built up and keep providers up-to-date with personal details.
"Keeping track of pension savings at every age is important but it is even more crucial for younger workers, who are likely to switch jobs more often, to actively manage this process."
Russell urged workers to consider the benefits of transferring previous pension pots into a new employer's scheme and said "seeking advice" was a must.
Pensions minister Steve Webb wants to change the system to a ‘pot follows member' model to tackle the problem of dealing with small pot abandonment and consolidation.
The system would see accrued pension money would follow a worker from job to job. However, legislation on the issue is yet to be drafted.
Clarke replacing Balkham
'Deep-dive analysis of client behaviour'
Ways to mitigate April’s increases
The best equity income funds examined