The conservation area operates in Windsor and Essex County in southern Ontario.
It's responsible for 19 conservation areas, including woods, marshes and beaches.
The ban, approved Thursday night, will be phased in over two years.
The ERCA will work with the Windsor Essex County Health Unit to enforce a policy that prohibits smoking first in high-use areas starting in 2014.
Areas where smoking will be banned next year include Holiday Beach, Hillman Marsh and the John R. Park Homestead.
There will be designated smoking areas only in parking lots and a few campsites at Holiday Beach.
All other conservation areas will become smoke-free in 2015.
Essex town Coun. Sherry Bondy, who sits on the ERCA board, said the move is "all about going green.
"Smoking isn't good for the environment. Second-hand smoke isn't good. But it's also the litter," she said. "We're concerned about cigarette butts and just how environmentally damaging they are."
Butt recycling program in B.C.
Earlier this week, an Ontario-based recycling company launched a cigarette butt recycling program in B.C.
Nina Prewal of TerraCycle Canada said cigarette butts are made from cellulose acetate, which does break down slowly in the environment but never loses its toxicity, thus poisoning essential links in the aquatic food chain.
Windsor city Coun. Jo-Anne Gignac, one of the ERCA board members who did not support the smoking ban, says: "I think it's going to be near impossible to enforce."
ERCA staff and the rest of the board believe the policy should be self-regulating, with proper signage and a public awareness campaign.
"Approaches like that, which we'll do in partnership with the health unit, are a very effective means of enforcing the policy," said ERCA general manager Richard Wyma.
There was talk of a partial ban earlier this year, but Kristy McBeth, who is manager of chronic disease and injury prevention, said the health unit's preference is a total ban.
"We want to create as many smoke-free spaces as possible to create a healthier community," McBeth told CBC News in October. "A total ban is definitely the way we would promote that."