The six-wheeled robotic rover landed on the planet safely in August. Its two-year mission was to find out if Mars once supported life.
Curiosity is equipped with an instrument called SAM (Sample Analysis at Mars), which can test samples and identify organic compounds.
Now, the scientists behind the project have claimed that the rover might have made an important finding.
Curiosity team's John Grotzinger told NPR: "We're getting data from SAM as we sit here and speak, and the data looks really interesting.
"This data is gonna be one for the history books. It's looking really good."
The discovery came from a soil sample from the planet, although the team refuse to divulge any additional information until they are sure about what they have found.
Grotzinger added that it could be several weeks before they are ready to make an announcement.
> NASA's Curiosity rover lands on Mars