The article reviews trends in glyphosate herbicide use in the United States and globally. Since the mid-1990s, glyphosate use has increased significantly, with over 1.6 billion kilograms applied in the U.S. from 1974–2014, accounting for 19% of global use. Globally, glyphosate use has increased 15-fold since the introduction of genetically engineered (GE) herbicide-tolerant crops in 1996. Two-thirds of U.S. glyphosate applications from 1974–2014 were sprayed in the last 10 years, while globally, 72% of applications occurred in the last 10 years. In 2014, farmers sprayed enough glyphosate to apply 1.0 kg/ha (0.8 pounds/acre) on every hectare of U.S.-cultivated cropland and nearly 0.53 kg/ha (0.47 pounds/acre) on all cropland worldwide. GE herbicide-tolerant crops now account for about 56% of global glyphosate use. In the U.S., no pesticide has come remotely close to such intensive and widespread use. Glyphosate will likely remain the most widely applied pesticide worldwide for years to come, and interest will grow in quantifying ecological and human health impacts. Accurate, accessible time-series data on glyphosate use will accelerate research progress. Glyphosate was first discovered in 1950 by a Swiss chemist and first sold as a herbicide in 1974. Its use expanded over the years, but was limited to areas where land managers wanted to kill all vegetation. The introduction of GE herbicide-tolerant crops in 1996 allowed for broader use of glyphosate, including post-emergence applications. This technological breakthrough made it possible to utilize glyphosate as a broadcast, post-emergence herbicide, thereby dramatically extending the time period during which glyphosate-based herbicides could be applied. Glyphosate use has increased significantly in the U.S. and globally, with the majority of use occurring on GE herbicide-tolerant crops. In the U.S., glyphosate use has increased from 0.36 million kg in 1974 to 1.37 billion kg from 1974–2014. Globally, glyphosate use has increased from 43 million kg in 1995 to 747 million kg in 2014. The use of glyphosate on GE herbicide-tolerant crops has increased significantly, with GE soybeans accounting for two-thirds of total hectares planted to GE crops globally. Glyphosate use on GE crops has increased dramatically, with the average rate of application per hectare per crop year rising from 0.47 kg/heThe article reviews trends in glyphosate herbicide use in the United States and globally. Since the mid-1990s, glyphosate use has increased significantly, with over 1.6 billion kilograms applied in the U.S. from 1974–2014, accounting for 19% of global use. Globally, glyphosate use has increased 15-fold since the introduction of genetically engineered (GE) herbicide-tolerant crops in 1996. Two-thirds of U.S. glyphosate applications from 1974–2014 were sprayed in the last 10 years, while globally, 72% of applications occurred in the last 10 years. In 2014, farmers sprayed enough glyphosate to apply 1.0 kg/ha (0.8 pounds/acre) on every hectare of U.S.-cultivated cropland and nearly 0.53 kg/ha (0.47 pounds/acre) on all cropland worldwide. GE herbicide-tolerant crops now account for about 56% of global glyphosate use. In the U.S., no pesticide has come remotely close to such intensive and widespread use. Glyphosate will likely remain the most widely applied pesticide worldwide for years to come, and interest will grow in quantifying ecological and human health impacts. Accurate, accessible time-series data on glyphosate use will accelerate research progress. Glyphosate was first discovered in 1950 by a Swiss chemist and first sold as a herbicide in 1974. Its use expanded over the years, but was limited to areas where land managers wanted to kill all vegetation. The introduction of GE herbicide-tolerant crops in 1996 allowed for broader use of glyphosate, including post-emergence applications. This technological breakthrough made it possible to utilize glyphosate as a broadcast, post-emergence herbicide, thereby dramatically extending the time period during which glyphosate-based herbicides could be applied. Glyphosate use has increased significantly in the U.S. and globally, with the majority of use occurring on GE herbicide-tolerant crops. In the U.S., glyphosate use has increased from 0.36 million kg in 1974 to 1.37 billion kg from 1974–2014. Globally, glyphosate use has increased from 43 million kg in 1995 to 747 million kg in 2014. The use of glyphosate on GE herbicide-tolerant crops has increased significantly, with GE soybeans accounting for two-thirds of total hectares planted to GE crops globally. Glyphosate use on GE crops has increased dramatically, with the average rate of application per hectare per crop year rising from 0.47 kg/he