The move means users searching for music tracks, albums and performers will return the standard Google information box but also with a new "Listen Now" ad and at least three links to streaming music services and stores.
It seems links for Google's Play music store are listed first as you'd expect, followed by rival services Rhapsody, Spotify and Apple's recently acquired Beats Music.
Google said music services pay on a per-click basis, according to the Wall Street Journal.
The Journal said music sellers for a while now have been able to purchase ad space, but Google's unified grouping and labeling of services in line with track and artist information is new.
A person familiar with the matter said the ads were "performing well."
"We're happy to help users quickly find legitimate sources for their favorite movies, music and more via Google search," said a Google spokesperson.
It is unknown when exactly Google rolled out the new feature, but sources told the WSJ that testing has been ongoing for the past few weeks.
It seems at this stage the new ads are US-only, or at least not yet available in Australia.
As we reported back in March music sales are down, but streaming is way up.