From the Catechism of the Catholic Church:

[b:2ar8vd3a]841[/b:2ar8vd3a] [i:2ar8vd3a]The Church’s relationship with the Muslims[/i:2ar8vd3a]. “The plan of salvation also includes those who acknowledge the Creator, in the first place amongst whom are the Muslims; these profess to hold the faith of Abraham, and [u:2ar8vd3a]together with us they adore the one, merciful God, mankind’s judge on the last day[/u:2ar8vd3a].”

Moslems worship the same God we do. However, because they lack the fullness of Jesus Christ and have instead followed the false prophet Mohammed, they are wildly incorrect in some of the things they believe about God (similar to how the Jews are incorrect in some of the things they believe about God).