The society lent £642m in the first six months of 2011, 61% up from £400m in the first half of 2010.
It also said it intends to increase new lending further this year to around £1.3bn
The average loan to value lent by Leeds in the first half of this year was 52% compared to 53% for the first half of 2010.
The mutual posted a pre-tax profit of £26.9m for the first half of 2011 up by 49% on 2010’s figure of £18m.
It said its cost income ratio reduced to 31% from 35% a year ago and is expected to be the lowest of any building society.
It also said it had attracted 21,000 new members taking total membership to over 685,000.
Capital and reserves increased to a record £553m from £515m a year ago.
Chief Executive, Ian Ward, said "Leeds Building Society has achieved another excellent set of financial results for the first half of the year and provided more capacity and choice to the UK mortgage market.
“New lending increased by 61% to £642m, which represents £275m above our market share.
“Almost a quarter of new loans, over £151m of completions, has enabled thousands of first-time-buyers to purchase their first home and this represents an 85% increase when compared to the same period last year.
"We intend to increase new lending further this year, to around £1.3bn, which will support many more first-time buyers onto the housing ladder and enable other borrowers to move their mortgage to us.”
