Global comparable sales for McDonalds have risen by almost 5 percent.
The multi-national fast-food giant reported a 4.5 per cent sales increase for 2010 so far.
Sales in May rose by 4.8 per cent.
Chief executive officer Jim Skinner said: "May marks another month of sustained sales growth, demonstrating the ongoing appeal of McDonald's unique combination of convenience, value and variety.
"Our focus on enhancing the McDonald's experience through affordable food choices, modernised restaurants and relevant marketing is giving customers even more reasons to visit McDonald's."
Recent product additions including Frappes and Shrek-themed Happy Meal products are believed to be behind a US comparable sale rise of 3.4 per cent.
European comparable sales were up 5.4 per cent while a 5 per cent increase was seen in the Asia/Pacific/Middle East and African markets.