This won't impact people with access to group plans through work, but if someone with a health condition wanted to start a business or switch to a job where there is no access to a group plan, this can make a huge difference. It's also a huge relief for young adults who are on the verge of leaving their parents' insurance.
To keep his liver from failing, 24-year-old Edward Pena has to take expensive immunosuppressive drugs for the rest of his life.
"Alone, without insurance, it costs like $1,000," said Pena. That's for a two-month supply. Pena, a Rio Hondo Community College student, said he wouldn't be able to afford that without coverage.
When he was 4 years old, a hepatitis-A infection led to a liver transplant. Insurance companies call what Edward has a "pre-existing condition."
"Some insurance companies would have a waiting period of three to six months if there was a pre-existing condition," said John Molina, chief financial officer of Molina Healthcare.
In the past, many insurance companies would either deny Pena coverage or charge him more.
These penalties affected millions of patients with numerous conditions including cancer, diabetes, heart disease and stroke.
But Molina says starting in 2014, new health care reform laws are changing all that.
"People who have pre-existing conditions don't have to worry about staying in their jobs -- they've got the freedom to move and they know that they'll be covered," said Molina.
Right now he remains under his parents' insurance.
In 2010, the federal government's expansion of coverage allowed Edward to stay on their plan until he's 26. Before that his family had no idea how they were going to cover his medical bills.
"I was relieved, I was really shocked. I wanted to jump for joy, my parents wanted to jump for joy," said Pena.
And when the time comes for Pena to shop for his own insurance plan, he's thrilled he won't be excluded.
"That's going to not just benefit me, it's going to benefit other individuals as well that are in my position, my situation," said Pena.
Covering people with chronic illnesses is expensive, so the hope is the cost could be spread among a larger population of sick and healthy people.
The U.S. Department of Health and Human Services found the number of people with pre-existing conditions could be as low as 50 million, or as high as 129 million.
Covered California: What you need to know