<p>Catalase (CAT) plays a central role in the protection of different cell types against the deleterious effects of hydrogen peroxide. In human, CAT is implicated in many physiological and pathological conditions including idiopathic male infertility. In this study we examined the association between CAT levels in seminal plasma with different sperm parameters and with <i>CAT–</i>262 C/T polymorphism and their risk for idiopathic male infertility in Algeria. Semen and blood samples were obtained from 111 infertile males and 104 fertile controls from the region of Eastern Algeria following informed consent. Standard semen parameters, DNA integrity, and CAT concentration in seminal plasma were evaluated. <i>CAT</i>-262C/T genotypes were screened using allele specific PCR. Seminal CAT activity was significantly different (<i>p</i><0.0001) between infertile males and controls, it was also markedly decreased in oligo-astheno-teratozoospermia (<i>p</i><0.0001), azoospermia (<i>p</i><0.0001), and normozoospermia (<i>p</i>=0.045) subgroups compared to controls. Positive correlations between CAT activity and semen parameters (volume, motility, concentration, and morphology) were detected, but not with sperm DNA integrity. There was no direct association between <i>CAT</i>-262C/T polymorphism and general male infertility. However, the results presented in this study showed that CAT activity is remarkably associated with the <i>CAT</i>-262T allele (<i>p</i>=0.001) and the different <i>CAT</i>-262C/T genotypes. This study highlighted the major differences in the seminal plasma CAT content between infertile and fertile males and the differences of CAT concentration between different <i>CAT</i>-262C/T genotypes carriers.</p