The findings, announced Monday at a meeting of the American Geophysical Union in San Francisco, are the latest to come from the rover Curiosity. Scientists said water and a mix of chemicals were detected in a scoop of the soil, but nothing required for microbial life was found.
"We have no definitive detection of Martian organics at this point, but we will keep looking in the diverse environments of Gale Crater," Sample Analysis at Mars Principal Investigator Paul Mahaffy said in a statement.
This follows earlier speculation that Curiosity had made a major discovery, but NASA shot down the idea last week, saying that wasn't the case.
Curiosity is about four months into its two-year mission. It is the most sophisticated spacecraft to go to Mars.
The rover Opportunity has been exploring craters in Mars' southern hemisphere since 2004. Opportunity's twin, Spirit, fell silent in 2010 after getting stuck in a sand trap.
The Associated Press contributed to this report.