"We don't want the pain of their loss rob them of the gift of their motherhood," said Father Michael Pfleger, who led the gathering near a memorial wall for the victims outside St. Sabina Church.
Each mother in attendance received a rose of remembrance and released a balloon in honor of their child.
"I still have this heavy ache in my chest," said Marsha Lee, whose son, Thomas, was killed in 2008. "So this morning as I got ready to come out I started reminiscing so I have all these buttons to show the different phases of his life."
The parent's support group Purpose Over Pain helped organize the Mother's Day remembrance.