Overall, the board reported Friday 7,570 homes sold last month compared with 7,683 a year ago.
Sales of condos slipped to 1,753 for the month, as detached and semi-detached home sales dropped two per cent and four per cent, respectively.
Townhouse sales jumped 15 per cent.
Board president Ann Hannah said new mortgage lending guidelines and the additional cost of the Toronto land transfer tax prompted some to put their buying decision on hold.
"Very strong annual sales growth in the first half of 2012 and an earlier peak in sales this spring compared to 2011 help explain more moderate sales this summer," Hannah said in a statement.
In Toronto, the average selling price in July was $476,947, up four per cent from a year ago, while the MLS home price composite index was up 7.1 per cent year-over-year.
New listings totalled 13,888 for the month, up from 12,407 a year ago.
The dip in sales in Toronto came as Vancouver, once the country's hottest real estate market, reported a sharp drop in sales and hit their lowest total for the month since 2000.
The Real Estate Board of Greater Vancouver reported Thursday 2,098 properties sold in the month, down 18.4 per cent from 2,571 in July 2011 and down 11.2 per cent from June's mark of 2,362, which was also the lowest total for that month since 2000.