Days after LA voters approved a law that limits the number of pot dispensaries in the city, HempCon, America’s biggest medical marijuana convention, kicked off in downtown Los Angeles.

The event includes exhibits from local medical marijuana dispensaries, as well presentations by attorneys and activists such as Richard Eastman, who helped start the first pot dispensary in LA in the mid 1990s.

Defense attorney Freddy Sayegh, Hempcon’s keynote speaker, said the event was scheduled months ago, before LA voters approved Measure D to limit the number of pot dispensaries in the city to 135, effectively forcing more than 300 shops to close.

Sayegh thinks Measure D will have a negative effect.

“You’re going to see the growth of underground sales of narcotics and trafficking,” Sayegh said.

Sayegh said despite LA’s efforts to reduce the number of dispensaries, there’s no denying Hempcon is good for the city’s economy, drawing some 20,000 visitors to downtown through Sunday.

“They get parking. All the hotels have been booked. The city gets a tremendous amount of money,” Sayegh said.

Attendee Robert Duncan said he's disappointed that Los Angeles voters passed the limitations.

"We live in California for Christ's sake," he said. "Colorado beat us to it. It's unfortunate they're not accepting of what it is."

LA City Councilman Bernard Parks, a former LAPD chief, said he has no problem with Hempcon being held in the city this year, but hopes in the future LA’s medical marijuana industry will be shut down.

“I hope we get to a point like 200 other cities in the state to ban it and stop going through the legal process,” he said.