"These groundbreaking electric tractors are poised to usher in a new era in improved safety, reduced environmental impact, and reduced cost of ownership," Juan Perez, chief information and engineering officer with UPS, said in a statement.
UPS' delivery fleet already includes trucks propelled by electricity, natural gas, propane and other alternative fuels. The company said it has been providing Tesla with data as part of an evaluation of the new truck.
Brewer Anheuser-Busch (BUD), which owns Budweiser and other brands, has placed an order for 40 all-electric Tesla Semis.
Tesla CEO Elon Musk says the truck can travel 500 miles on an electric charge even with an 80,000-pound load, and also has autonomous driving capabilities. The company is planning to build a worldwide network of solar-powered "megachargers" that could get the trucks back up to 400 miles of range after charging for only 30 minutes.
Production is scheduled to begin in 2019.