However, Judge Suzana Pereira said Edson Cholbi do Nascimento, who must surrender his passport to the Sao Paulo court this week, can remain free while he appeals - a process which can take years in Brazil.
The judge said she could not reveal many details of last week's ruling because both parties agreed to handle the case privately, but she found enough proof to convict do Nascimento.
The 43-year-old, who played as goalkeeper and is now a coach for Santos, had denied the charges, although he said he had used drugs out of curiosity after he quit professional football.
He spent six months in a maximum-security prison in 2005 after being arrested with 50 others in a sweep aimed at a gang in the port city of Santos. Prosecutors said he was associated with the criminal group.
Pele's adviser, Jose Fornos Rodrigues, said the star had no comment on the case.