Employees were at the George R. Brown Convention Center in downtown Houston for the conference, which was being held for distributors.
At least eight people were injured in the mass shooting at company's facility. The gunman, who was reportedly a disgruntled employee, is dead, police told ABC News.
READ MORE: Milwaukee shooting at Molson Coors leaves fatalities, injuries, mayor says; shooter dead
ABC13 learned the conference included a mix of employees as well as distributors from across the country.
It was a three-day conference that began on Monday. A reception that was planned after the conference was cancelled along with other events.
CEO Gavin Hattersley addressed attendees making them aware of the shooting and then reportedly flew back to Milwaukee.
"He just came out and released a statement and he was on his way back to Milwaukee, obviously, to get back to the brewery," a distributor told ABC13. "It's obviously something that's heartbreaking."