"I'm still completely convinced that the martyr Arafat did not die a natural death, and I will keep trying to get to the truth," Suha Arafat told AFP.
"I'm shocked by (the results of) the French medical report, which I only received four pages of to look at," she said.
The French experts' findings, released yesterday, differed significantly from those of Swiss scientists, who said last month their research offered some support for the suggestion Arafat was killed by polonium poisoning.
"How the French haven't found anything is completely illogical," she added.
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A source close to the French investigation said yesterday it "rules out the poisoning theory and goes in the sense of a natural death".
The circumstances of Arafat's death aged 75 at a military hospital near Paris in November 2004 after a sudden deterioration in his health have long been mired in rumour and speculation.
French doctors were unable to say what killed him and an autopsy was never performed, at the request of his widow.
Some 60 samples were taken from Arafat's remains in November 2012 and divided between Swiss and Russian investigators and a French team carrying out a probe at his widow's request.
Many Palestinians believed he was poisoned by Israel -- a claim repeatedly denied by the Jewish state.
Israeli foreign ministry spokesman Yigal Palmor told AFP the results of the French probe were "no surprise".