The 29-year-old woman had admitted during the trial in the northern city of Flensburg to secretly giving birth and immediately killing the five newborns between 2006 and 2012.
Three of the infants were suffocated and two stabbed with scissors, the court concluded, finding the woman, who is from the town of Husum and was not named, guilty of five counts of manslaughter.
Although the trial was unable to clarify exactly why the woman killed the infants, she had said in questioning by the police that her husband did not want any more children.
Presiding judge Michael Lembke said that, when it came to pregnancy and birth, the defendant had virtually "suppressed, ignored, completely blanked it out" and that the labour pains had taken her by surprise.
But her actions were always unplanned, he said. Although an offender, she was "no monster", he added.
A psychiatric assessor ordered by the court said her motive remained unclear.
The woman, who has two children of school age, gave birth at home or in the woods. Two bodies were found in a paper recycling plant and a car park in 2006 and 2007.
Last year when the woman was asked to provide a routine DNA sample as part of investigations, she turned herself in and took police to the bodies of three further babies hidden in her cellar.
Her husband was described at the time the woman was charged as "completely devastated". He told police he knew nothing about the pregnancies.
The case is thought to be the worst to come to light in Germany since 2005, when a mother was sentenced to 15 years in prison after killing eight of her newborns.