Variation in the gene encoding cyclooxygenase-1 (COX-1) is involved in the process of aspirin resistance. This study investigated the genetic variations in the COX-1 gene. The 4 coding regions of the human COX-1 gene in 90 pediatric patients (median age of 6.5 months, 55% males) with cardiovascular anomalies were screened using DNA sequencing. Twenty coding-region variants causing amino acid substitutions as well as 2 new non-synonymous polymorphisms were identified. All variants were compared with an independent Caucasian population (N = 24 unrelated individuals). Most of the discovered polymorphisms were rare, although some variants resulted in amino acid changes occurring at a frequency >5% (W8R, P17L, Q41Q, Q240Q, D189E, and P188P). In addition, 2 new non-synonymous polymorphisms (F200L and D189E) were identified. These findings demonstrated novel genetic variants of the human COX-1 gene. Future studies characterizing the functional impact of these variants are warranted.