The FSA forced 82 firms to change or withdraw misleading advertisements in the six months to March.
The regulator's first report into financial advertising complaints revealed that 219 cases were investigated in the six months to March, with 126 coming from its compliance monitoring unit. The remaining 93 came from members of the public.
The most common source of misleading advertising was the national press, followed by direct mailshots and websites.
FSA consumer director, Anna Bradley, said: "On eight occasions the adverts were so poor that we also insisted firms write to customers who had already responded, offering them their money back.
"We're also going to strengthen the advertising rules on these products, to ensure that firms do a better job of telling you what you need to know to make an informed decision."
