Officers responded to a call of a vicious dog in the 6500 block of Chester Avenue at about 10:35 a.m.
When police arrived they shot the dog, but it was still alive. The two children were bitten on the leg.
Police said one of the children was taken to Children's Hospital of Philadelphia. The child's condition was unknown.
A second child was also taken to a hospital. Their condition was also unknown.
No police officers were injured.