The four bases contained in deoxyribonucleic acid (DNA) are:

* Adenine (A)

* Guanine (G)

* Cytosine (C)

* Thymine (T)

These bases are attached to a sugar-phosphate backbone to form the DNA molecule. Adenine always pairs with thymine (A-T), and guanine always pairs with cytosine (G-C). This pairing is what gives DNA its double helix structure.