It's a first for the district and one they hope will help close the achievement gap among African-American children.
The Montessori Method teaches children subjects based on their level of development.
"For the child to develop at their own pace, it is focused completely on the individual inside a social group," said Montessori Implementer Emily Green.
William Cobb Elementary School has used this method to teach their preschoolers. On Monday, they added kindergarten. The goal is to eventually expand the Montessori program through 5th grade.
Other cities have had success with the Montessori program. The Milwaukee public school system has had it for 20 years. Today it has four public schools, pre-k through eighth, serving 3,000 kids.
San Francisco is taking its cues from Milwaukee's successes.
"And it's had a great impact on African Americans and minority students in closing the achievement gap, so that is very exciting for us so we hope that is one more tool we can use," said Superintendent Carlos Garcia.
The school district wants to offer parents an alternative to the traditional classroom.
Still, like everybody else, these Montessori children will have to take California's standardized test beginning in the second grade.
"If you look at the test scores of kids who go through Montessori they actually outperform other kids so it's not for everybody but it's certainly a great program. I think it's going to have a very positive impact on our school program," said Garcia
Three years ago, William Cobb Elementary School nearly closed because of the district's declining enrollment.
Today their expanded Montessori program is suddenly getting more parents interested.
"I can't change the cost of housing, I can't change the cost of living or what a family can get on a Section 8 voucher, but what I can do is bring them the best in quality education," said Principal Pat Forte.
If it works at William Cobb, the district is ready to bring the Montessori Method to other schools.