The Italian court, in Ivrea, agreed that a man's brain tumour was linked to his mobile phone use.
It awarded Robert Romero 500 euros (£418/$535) a month in compensation.
He had claimed that using his business mobile phone for three or four hours a day, over a period of 15 years, led to the growth of the benign tumour.
The money will be paid by a body established to compensate people for work-based injuries.
There could yet be an appeal against the ruling, and the legal reasoning behind the judge's decision is not due to be released for at least a few days.
"We know that many people are concerned about a possible connection between mobile phone use and the development of brain tumours," said Dr David Jenkinson, chief scientific officer for the Brain Tumour Charity.
"However, the global research projects that have been conducted so far, involving hundreds of thousands of people, have found insufficient evidence that using a mobile phone increases the risk of developing a brain tumour."
The decision of the court did not change the evidence, he added.
"Of course, it is right that researchers continue to explore whether any such link exists," said Dr Jenkinson.
Mr Romero, whose profession was not reported, said he wanted people to be more aware about mobile phone use but did not want to "demonise" the devices.
His lawyer, Stefano Bertone from the law firm Ambrosio and Commodo, told the BBC his client currently has no plans to sue any of the handset manufacturers or the mobile phone industry itself.
He added that the firm has other cases in other parts of Italy.
"We have also been approached by an interesting number of people in the last 24 hours saying they have experienced the same kind of thing. And they can show they have accumulative use of mobile phones that's exceeding 1,000 hours," he said.
"No-one can pretend with definitive certainty to assess a legal case. Most opponents say there is no scientific certainty so therefore it is not true. That is not the case."
Mr Bertone highlighted a continuing o study by the National Toxicology Program in the US.
Preliminary findings released in 2016 suggested a "low incidence" of brain and heart tumours in male rats exposed to doses of radiofrequency radiation totalling up to nine hours a day over a two-year period.
However, as it is not finished, the study has not yet been scrutinised by other scientists, a process known as peer reviewing, which is generally considered an essential stage of evaluating research.