Around 20 firefighters responded to a home on Crystal and Yale avenues on Thursday afternoon.
The report came in as an attic fire.
Fire officials say they then found roughly 300 marijuana plants inside the home, and the attic fire was likely an electrical issue.
"Our fire investigators came out, and there was some power coming into the building. It was helping facilitate a marijuana grow operation. That's determined to be the cause of the fire," said Fresno fire captain Kenny Garcia.
No one was inside the home when the flames broke out, and no one was injured.