Objectives: Endometriosis is a potential pre-malignant gynecological condition harboring multiple gene mutations in the endometriotic lesions. Evidence has implicated the possibility that caspase recruitment domain family member 14 (CARD14) mutations might exist in ovarian endometriosis. It is questioned whether ovarian endometriosis harbors CARD14 mutations. Materials and Methods: The authors recruited and analyzed a cohort of 101 ovarian endometriosis samples for the presence of CARD14 mutations via sequenced the coding and intron/exon boundary regions of the CARD14 gene. Results: A novel heterozygous somatic CARD14 mutation, p.R470C (c.1408C>T), was identified in two out of 101 (2.0%) endometriotic lesions. The mutated samples were 30-and 31-years-old and both had a history of childbirth. No CARD14 mutations were detected in the remaining 99 samples with ovarian endometriosis. Protein structure modeling results showed CARD14 p.R470C mutation resulted in protein structural changes. These combined results implicated that this mutation might be damaging. However, no association was observed between the main clinical features and CARD14 mutations in this sample cohort. Conclusion: The authors identified a potential damaging CARD14 somatic mutation in 2/101 (2.0%) endometriotic lesions with ovarian endometriosis for the first time, and this mutation might play an active role in the development of ovarian endometriosis.