The new product sits alongside its discounted rate BTL mortgage, which was launched in April.
The fix is available for employed, self employed and retired applicants with a minimum income of £20,000 up to 70% LTV.
Mike Taylor, sales and marketing mManager at The Mansfield, said: “As a long time supporter of the buy-to-let market, we can see the strong growth in property values is leading to a healthy lettings market.
“With the new rate fixed for two years, landlords can take advantage of a great price and our flexible lending.”
He added: “I know this product will be welcomed by our professional introducers, who have told us how important this channel is in the property market and I am sure there’ll be a lot of activity in the coming weeks from brokers who can see the value we are offering to their clients.”