The agency said 19.9 percent of Canadians, or 5.8 million people above the age of 12 smoked in 2011, down from 25.9 percent in 2001.
Of them, nearly 4.4 million said they smoked cigarettes on a daily basis.
Encouraging to health officials, the number of teen smokers 15 to 17 fell from 20.8 percent in 2001 to 9.4 percent last year.
Heavy drinking, considered as consuming five or more alcoholic drinks per occasion, rose to 19 percent of people at least 12 years of age, up from 17.3 percent in 2010, the survey said.
StatsCan said as for obesity, rates were "virtually unchanged" from 2009.
"In 2011, 18.3 percent of Canadians aged 18 and older, roughly 4.6 million adults, reported height and weight that classified them as obese," the agency said. "Obesity rates were highest in the age group 55 to 64 and lowest among teenagers aged 18 to 19."
When it came to physical activity during leisure time, 53.8 percent of Canadians described themselves as "moderately active," which the agency said would constitute a daily 30-minute walk or an hour-long exercise class three times a week.