A team at the Carnegie Institution for Science in the US who analysed 10 Martian meteorites, which span 4.2 billion years of the planet's history, found that carbon present in the rocks came from the Red Planet and was not the result of contamination on Earth.
The Martian rocks analysed by the team including the new Tissint meteorite that fell into the Moroccan desert in 2011.
But the research, details of which have been published in the journal Science, also shows that the Martian carbon did not come from life forms.
Instead, the scientists believe that the "reduced carbon" -- carbon that is chemically bonded to hydrogen or itself -- in the meteorites was created by volcanic activity on Mars.
This is evidence "that Mars has been undertaking organic chemistry for most of its history," they argued.
The team's leader Dr Andrew Steele told BBC News: "For about the last 40 years we have been looking for a pool of what is called 'reduced carbon' on Mars, trying to find where it is, if it's there, asking "does it exist?"
"Without carbon, the building blocks of life cannot exist... So it is reduced carbon that, with hydrogen, with oxygen, with nitrogen make up the organic molecules of life."
He said the new analysis has answered the first question.
"This research shows, yes -- it does exist on Mars and now we are moving to the next set of questions.
"What happened to it, what was its fate, did it take the next step of creating life on Mars?"
He hoped the next mission to land on the Red Planet -- the Mars Science Laboratory, also known as the "Curiosity" rover -- will shed more light on the big question.
"The question 'are we alone' has been a big driver of science but it relates back to our own origins on this planet. If there is no life on Mars, why? It allow us to make a more informed hypothesis about why life is here."
"We'll see if there are hints that Mars is not a dead planet," Steele added.