Selenium (Se) is an essential micronutrient for human biology that executes its functions as the amino acid selenocysteine via selenoproteins, which have important functions, such as, antioxidant, immunomodulatory, thyroid metabolism and human fertility. Se nutritional status is assessed using the quantification of blood Se biomarkers influenced by several factors, including diet, age, gender, smoking status, alcohol consumption, health condition and genetic characteristics of individuals. Nutrigenetic studies have identified single nucleotide polymorphisms (SNPs) in 2 selenoproteins that might clarify the high variability in values reported for biomarkers of Se nutritional status in different populations and the response of these biomarkers to Se supplementation with either organic or inorganic forms of Se. This review aims to (1) define the basic aspects of Se biology, (2) describe the current most commonly used biomarkers of Se nutritional status and, (3) provide a state of the art of associations observed between functional SNPs in selenoproteins and biomarkers of Se status in healthy populations.