Your sponsored child’s number is on any letter that you receive from your child. You will find it printed above the barcode that is attached to every letter your child sends, along with his or her name. You will also find it beside his or her name on the letter writing paper included with every child letter (on the left side of the page).
Child numbers always begin with two letters (indicating country) followed by seven digits.
You can also view this information through your MyCompassion account