The use of drugs and nutritional supplements to enhance sports and exercise performance has been widespread at all levels of participation and competition, albeit to a varying extent. The World Anti-doping Agency (WADA) was established to address the problem of drug use by athletes for their potential ergogenic effects. The primary purpose of WADA is to protect athletes worldwide, promote the values of clean sport, and preserve the spirit of sport. WADA’s primary role is to develop, harmonize, and coordinate anti-doping rules and policies across all sports and countries. In addition, WADA engages in a wider range of other activities including scientific and social science research; education; intelligence and investigations; development of anti-doping capacity; and monitoring of compliance with the World Anti-Doping Program. The detection of a prohibited substance or its metabolite or laboratory markers in an athlete’s sample (urine, blood, or other as appropriate) constitutes doping. The categories of WADA-prohibited substances and methods include anabolic agents, peptide hormones and their releasing factors, growth factors and growth modulators, erythropoiesis promoting agents and methods, beta-2 agonists, hormone and metabolic modulators, and masking agents such as diuretics. Optimal baseline nutrition, treating any micronutrient deficiencies, and maintaining appropriate fluid and electrolyte balance are all essential for optimal sports performance. Although a large number of nutritional supplements are being marketed for their purported ergogenic effects, only a handful have been shown to have such effect to a variable degree; these include caffeine, creatine, nitrate, beta-alanine, and sodium bicarbonate.