"Ronaldinho, of Barcelona, asked the technical staff of the Brazilian national team to be excused the Copa America, on the grounds of tiredness and the need for a holiday," said the CBF in a statement.
Ronaldinho's request came three days after midfielder Kaka also asked to be left out of the competition and in spite of comments from coach Dunga that he wanted to take a full-strength squad.
Brazilian media had been speculating for some time that Ronaldinho wanted a rest and his request will heighten speculation that his relationship with Dunga is under strain.
Dunga has left Ronaldinho out of the starting line-up on several occasions and said that the former World Player of the Year will not be given special treatment.
Ronaldinho has often been criticised for saving his best for Barcelona. He went nearly two years without scoring for Brazil until hitting the target twice in the 4-0 win over Chile in March.
PROFESSIONAL COMMITMENTS
The Copa America, in which Brazil are defending champions, will provide Dunga with his first competitive matches since he took over following their lacklustre performance at the last World Cup.
Ronaldinho's letter bore a striking resemblance to the one written by Kaka.
"It is well known to you that during the last few years I have been subjected to intense and uninterrupted physical activity," he said.
"I have been unable to take the recommended and necessary periods of rest which may, on occasion, have an influence on the high level of performance demanded by my professional commitments with my club and, principally, the Brazilian national team.
"I have always shown satisfaction and a sense of responsibility in serving Brazil during my career. Wearing the yellow shirt is, for me, a motive of pride and love for my country," he said.
"I'm grateful for the respect and the attention which the organisation (CBF) has always shown towards me and, thanks to the excellent and open relationship that we share, I ask for your understanding in my request.
"I hope that I will soon be able to serve Brazil with the pride and satisfaction I have always shown and I'm certain that the future will bring me marvellous moments with Brazil.
Brazil face Mexico, Ecuador and Chile in their first-round group.
