The comet assay is one of the techniques that has been extensively used to assess DNA damage in both the somatic cells and the spermatozoa over the past years. The results are robust and, as difference with other strategies to assess DNA damage, information about the presence of single-strand breaks (SSBs) or double-strand breaks (DSBs) can be obtained. The characterization of SSBs and DSBs profiles provides a more comprehensive analysis of sperm DNA quality for their clinical application. In this chapter, the utility comet assay as a diagnostic test for male infertility and as a prognostic test for assisted reproductive techniques is summarized.