Approximately 6.1 percent of high school seniors reported using marijuana in 2010. That's up from 5.2 percent in 2009.
Marijuana use by eighth and 10th graders also increased.
Meantime, the study also found that binge drinking is on the decline.
Some 23.2 percent of high school seniors reported having five or more drinks in a row. That's down from 25.2 percent a year earlier. The binge rate for this age group peaked at 31.5 percent in 1998.
The study also found that the use of ecstasy, which had declined in the early 200s, is on the increase again.
The survey conducted by the University of Michigan covered 46,482 students in 396 schools.
The Associated Press contributed to this report.
