There are four different nitrogenous bases found in DNA:

1. Adenine (A)

2. Guanine (G)

3. Cytosine (C)

4. Thymine (T)

These bases pair up in a specific way: adenine always pairs with thymine (A-T), and guanine always pairs with cytosine (G-C). This pairing is essential for DNA replication and the genetic code.