The bank is launching a two-year fix at 4.49% and a five-year fix at 5.39% tomorrow.
Both products come with a £1,999 arrangement fee and are available for loans up to £500,000.
Clydesdale previously lent up to a maximum LTV of 75% on buy-to-let.
A spokesman for the lender says the rates are among the most attractive being offered in this segment of the buy-to-let market.
He says: “We have been growing the amount of business we do via brokers over the past year and this is an extension of that.
“There is clearly a lot of demand out there from brokers, particularly for higher LTV buy-to-let products, so we are responding to that demand.”
Leeds Building Society and Aldermore increased their maximum LTV on buy-to-let to 80% earlier this month.