Norwich Union is giving free critical illness cover to new customers taking out SafeGuard Income Protection policies between June and September 30, 2000.
Eligible customers, who must be aged between 18 and 49, will each receive critical illness cover worth £10,000 for 12 months as a free add-on to the SafeGuard policy.
The minimum premium is £10 monthly or £114.30 annually.
NU Healthcare income protection manager Nick Homer said: "Traditionally, people seeking cover against disability have chosen either an income protection or a critical illness policy as the common perception is that they are similar products.
"In fact the cover and benefits are very different and the two products actually complement each other."
Critical illness pays a lump-sum benefit for a one-off ailment, usually in case of incapacity, while income protection provides long-term financial security.
Homer adds: "In the past, income protection insurance has come in a poor second to other products when it comes to protecting the mortgagee.
"This is arguably due to the historic problems of underwriting delays and its failure to provide all-round protection against unemployment as well as accident and sickness."