Supporters say the money would be used on existing health and stop-smoking programs and would raise $735 million.
Supporters of Prop 29 include health care providers, Mayor Antonio Villaraigosa and people like cancer survivor and Tour de France champion Lance Armstrong.
"This has in many ways become a political issue, and for the first time in my life, for the first time in my life as a cancer survivor, we're learning that, but we're on the right side," said Armstrong.
The opponents of Prop 29 agree that fighting cancer is the right thing to do. But they don't believe that a massive tax hike is the right way to do it, even if it only targets the people who use the cigarettes.
David Spady is state director of a taxpayers association called Americans for Prosperity. The association, along with the tobacco industry, is spending millions to defeat Prop 29, and much of their investment can be seen on television with anti-Prop 29 ads.
"There's nothing that mandates this money stay in California or even in the country, this money can be spent on cancer research anywhere in the country or outside the country," said Spady.
Supporters of the tax strongly disagree, and say the word California is inserted throughout Prop 29.
The tobacco industry has spent about $40 million so far to defeat Prop 29, but if it passes it will take effect in the fall.