A cyclobutane pyrimidine dimer (CPD) is a type of DNA damage that occurs when adjacent pyrimidine bases in DNA, typically thymine or cytosine, form covalent bonds with each other due to exposure to ultraviolet (UV) radiation. When UV light hits DNA, it can induce the formation of covalent bonds between the C=C double bonds of adjacent pyrimidine bases. In the case of CPD, the most common dimers formed are between two adjacent thymine or cytosine bases. Pyrimidine-Pyrimidone (6-4) photoproducts (64-PPs), and Dewar valence photoisomers are also produced by UV exposure. The formation of these UV damage can cause distortions in the DNA structure, which can interfere with DNA replication and transcription processes if left unrepaired. UV-induced DNA damages are particularly problematic because they can lead to mutations if not repaired by the cell’s DNA repair mechanisms. If these mutations occur in critical regions of the genome, they can contribute to the development of diseases such as cancer. In this chapter, we present a technique to quantify the amount of UV-induced DNA damages in cells by ELISA-based methods.