El Monte Police officers were on the scene during the fire assisting in evacuating the area.
Area residents were back home Monday night, but firefighters remained on the scene to ensure there were no "hot spots" to flare up in the burned out complex.
The Laundromat was a complete loss and two other units in the strip mall suffered damage in the blaze.
"One unit was fully involved. They did a great job of stopping it," said Matt Levesque, L.A. County Fire Dept. spokesman. "Just caused a little minor damage on either side of the main fire, with some minor damage and no injuries."
The Lower Asuza Plaza strip mall is located on Lower Azusa Rd. and Santa Anita Blvd. in El Monte.
Emergency responders were hampered by a traffic closure on Santa Anita Blvd. due to a truck striking a rail bridge overpass. The structural integrity of the overpass was being examined after a hit-and-run accident.
No injuries were reported.
The cause of the fire was under investigation.