California bans the use of tanning beds for under 18s. California is the first US state to do so to protect minors from increased skin cancer risks.
Brown signed a bill into law Sunday after dismissing arguments from the tanning industry that the current law -- which requires children between age 14 and 18 to get parental consent -- was sufficient.
"California's decision to ban under 18 year olds from tanning beds is a welcome step in the right direction for a needless exercise that is a known and significant health threat," Wendy K.D. Selig, head of the Melanoma Research Alliance.
"It is well documented that indoor tanning contributes to skin cancer, including melanoma, which can have fatal consequences," she added.
The MRA cited studies compiled by the World Health Organization which said there was a 75% increased risk of melanoma -- the most common cancer in US women age 25-29 -- in indoor tanning bed use.
The author of the new law in California -- which enjoys year-round sunshine, in the south of the state at least -- also praised Brown, saying the move was backed by doctors, nurses and the American Cancer Society.
"I praise Governor Brown for his courage in taking this much-needed step to protect some of California's most vulnerable residents -- our kids.... If everyone knew the true dangers of tanning beds, they'd be shocked," he said.