Three companies received the notice including Bird, Lime and Spin.
The increase of electric scooters and dockless bikes on the City's streets has gotten mixed reaction.
The transportation alternatives help reduce traffic and pollution but can also block sidewalks and curb ramps.
VIDEO: What's up with those scooters parked around SF?
VIDEO: What's up with all those scooters parked around SF?
On Friday the city's public works department seized 66 scooters they say were blocking traffic.
Riders use an app to rent an e-scooter and can park it anywhere when they're done. Some end up falling over and blocking sidewalks and entryways.
Many riders are seen breaking laws - riding on the sidewalk, without helmets, and faster than the 15 miles per hour speed limit.
A spokesperson for Bird - one of the scooter companies - said they will work with the city to find a solution.
RELATED: Dockless scooters, bikes have bumpy launch in SF, San Jose, cities hustle to regulate
Part of a statement says, "We will continue to build upon bird's user education so that our growing use base becomes accustomed to considering their fellow San Franciscans and parks safely out of the right of way."
Click here to read a letter from the SFMTA on dockless bikes and scooters.
Click here for more stories, photos, and video on bikes.