The state-of-the art detector, which weighs 8,500 kilograms, is expected to stay in operation through the lifetime of the space station, until 2020 or longer.
The results "could help foster a new understanding of the fields of fundamental physics and astrophysics," NASA administrator Charles Bolden said in a statement Wednesday.
"I am confident that this is only the first of many scientific discoveries enabled by the station that will change our understanding of the universe," he said.
CERN director general Rolf Heuer said the findings so far were "a great example of the complementarity of experiments on Earth and in space."
Searches for dark matter are also being carried out at CERN using the Large Hadron Collider, the world's largest and most powerful particle accelerator, and other laboratories.
"Working in tandem, I think we can be confident of a resolution to the dark matter enigma sometime in the next few years," Heuer said.