Abstract: Objective To study the association of the level of advanced oxidation protein products (AOPPs) in seminal plasma with teratospermia and the outcome parameters of in vitro fertilization (IVF). Methods We conducted a cross-sectional study among 272 male patients receiving assisted reproduction treatment in the Center for Reproductive Medicine of our hospital between October, 2018 and March, 2019. The levels of seminal AOPPs and reactive oxygen species (ROS), demographic data, sperm parameters and IVF outcome parameters were analyzed for all the patients. According to the percentage of sperms with normal morphology, the patients were divided before IVF into teratozoospermia group and normal sperm morphology group, and those in teratozoospermia group were further divided into 3 subgroups with mild, moderate and severe teratozoospermia. The patients were also divided on the day oocyte retrieval into 2 groups with fertilizing rates lower (group I) and higher (group II) than the median rate. Results We found a significant negative correlation of seminal AOPP level before treatment with the percentage of normal sperm morphology (P=0.003) and seminal ROS level (P=0.013). The seminal levels of AOPPs (P= 0.027) and ROS (P=0.036) were significantly elevated in patients with teratospermia, and seminal AOPP level was significantly higher in severe teratospermia group than in mild (P=0.019) and moderate (P=0.015) teratospermia groups. The seminal levels of AOPPs (P=0.003) and ROS (P=0.017) on the day of oocyte retrieval were negatively correlated with the fertilization rate in IVF cycles, and the levels of AOPPs (P=0.049) and ROS (P=0.036) were significantly higher in group I than in group II. Conclusion An elevated level of seminal AOPPs may indicate an increased risk of severe teratospermia and a lower fertilization rate in IVF.