NutraSweet is a company that makes and sells aspartame, an artificial sugar substitute. NutraSweet® is also the brand name for the sweetener aspartame, which was discovered in 1965 by James M. Schlatter, a chemist working for G.D. Searle & Company. After initial rejection by the FDA due to studies linking it to brain cancer, FDA commissioner Arthur Hayes approved aspartame for human consumption in 1981. In 1983, Hayes quit the FDA under allegations of accepting corporate gifts and joined Searle's public-relations firm as senior medical advisor. In 1985, G.D. Searle & Company was purchased by Monsanto. In this merger, Searle's aspartame business became a separate Monsanto subsidiary, the NutraSweet Company.

Despite ongoing controversy as to whether aspartame is safe or harmful, NutraSweet has gained regulatory approvals permitting its sale in more than 100 countries. Despite losing market share in recent years to sucralose due to the perceived health risks , the NutraSweet company states that its product is used in over 5,000 products and consumed by some 250 million people worldwide.

The U.S. patent on aspartame expired in 1992, and the aspartame market is now hotly contested between the NutraSweet Company and other manufacturers, chiefly the Holland Sweetener Company.

In March 2000, Monsanto sold its artificial sweetener division (including NutraSweet) to Merisant.