We believe in one God, the Father Almighty, maker of all things visible and invisible;
    And in one Lord Jesus Christ, the Son of God, the only-begotten of his Father, of the substance of the Father, God of
God, Light of Light, very God of very God, begotten, not made, being of one substance [homoousion] with the Father. By whom all things were made, both which be in heaven and in earth. Who for us humans [anthropoi] and for our salvation came down [from heaven] and was incarnate and was made human [anthropos]. He suffered and the third day he rose again, and ascended into heaven. And he shall come again to judge both the quick and the dead.
    And [we believe] in the Holy Ghost.
    And whosoever shall say that there was a time when the Son of God was not, or that before he was begotten he was not, or that he was made of things that were not, or that he is of a different substance or essence [from the Father] or that he is a
creature, or subject to change or conversion--all that so say, the Catholic and Apostolic Church anathematizes them.

EXCURSUS ON THE WORD HOMOUSIOS.
    The Fathers of the Council at Nice were at one time ready to accede to the request of some of the bishops and use only scriptural expressions in their definitions. But, after several attempts, they found that all these were capable of being explained away. Athanasius describes with much wit and penetration how he saw them nodding and winking to each other when the orthodox proposed expressions which they had thought of a way of escaping from the force of. After a series of attempts of this sort it was found that something clearer and more unequivocal must be adopted if real unity of faith was to be attained; and accordingly the word homousios was adopted. Just what the Council intended this expression to mean is set forth by St. Athanasius as follows: "That the Son is not only like to the Father, but that, as his image, he is the same as the Father; that he is of the Father; and that the resemblance of the Son to the Father, and his immutability, are different from ours: for in us they are something acquired, and arise from our fulfilling the divine commands. Moreover, they wished to indicate by this that his generation is different from that of human nature; that the Son is not only like to the Father, but inseparable from the substance of the Father, that he and the Father are one and the same, as the Son himself said: 'The Logos is always in the Father, and, the Father always in the Logos,' as the sun and its splendour are inseparable."
 

    We believe in one God, the Father Almighty, maker of heaven and earth and of all things visible and invisible.
    And in one Lord Jesus Christ, the only begotten Son of God, begotten of his Father before all worlds, Light of Light, very God of very God, begotten not made, being of one substance with the Father, by whom all things were made. Who for us humans [anthropoi] and for our salvation came down from heaven and was incarnate by the Holy Ghost and the Virgin Mary, and was made human [anthropos], and was crucified also for us under Pontius Pilate. He suffered and was buried, and the third day he rose again according to the Scriptures, and ascended into heaven, and sitteth at the Right Hand of the Father. And he shall come again with glory to judge both the quick and the dead. Whose kingdom shall have no end.
    And [we believe] in the Holy Ghost, the Lord and Giver-of-Life, who proceedeth from the Father, who with the Father and the Son together is worshipped and glorified, who spake by the prophets. And [we believe] in one, holy, Catholic and Apostolic Church. We acknowledge one Baptism for the remission of sins, [and] we look for the resurrection of the dead and the life of the world to come. Amen.
 
 

texts taken from http://www.cs.cmu.edu/People/spok/catholic/teaching.html#official