McDonald's Holdings Co. (Japan) Ltd. says its sales in August hit the highest level for a single month since the company's founding in 1971, rising 5 percent from a year earlier to ¥51.39 billion.

The introduction of new chicken dishes in July and a discount on Big Mac hamburgers as well as brisk sales of iced coffee and other drinks amid the scorching summer helped boost overall sales, the fast food chain said.

The company reported its previous record monthly sales in March, at ¥49.73 billion, when it sold large hamburgers called the California Burger and the Texas Burger for a limited period.