The German trainer has declared that he will not designate somebody to shadow the 27-year-old forward as he would require several men to stop the Portuguese ace
The Real Madrid forward is widely regarded as the Seleccao's biggest attacking threat and heads into the tournament in superb form, having scored 60 goals in all competitions in 2011-12.
Low is aware of the former Manchester United man's qualities, but insists he cannot entrust a player with the sole responsibility of tracking the forward's movements.
"If I will have Philipp Lahm marking Ronaldo? I will decide where he will play only when I arrive in Poland," Low told reporters.
"There is no sense in putting one player on Ronaldo all the time.
"I would need three or four players to stop him. I do not want one-on-one situations against him."
Germany will play against Portugal in their Euro 2012 opener on June 9 before locking horns with Netherlands and Denmark.