"1 in 88 children has been identified with autism," reports Dr. Coleen Boyle of the Centers for Disease Control.
Experts acknowledge this increase might simply be explained by better diagnosis.
"What we don't know, if we should be alarmed by yet, is if this is a truly a change in the number of children who have autism, or if it's a matter of we're recognizing it better," explains Yale's James McPartland.
The CDC study shows autism cases jumped 23 percent from 2006 to 2008, and spiked 78 percent when compared to 2002.
The 2008 numbers show autism spectrum disorders are five times more common in boys than girls
and the largest increases among Hispanic and African-American children.
Older parents and premature births are suspected factors, but the cause remains a mystery.
"The prevailing scientific idea is it's something that affects the brain predominantly in utero -- so in other words it's either genetic or environmental factor in utero," says Dr. Max Wiznitzer.
The study shows the average age of diagnosis is down to 4-years-old, but experts say that's not good enough.
They're hoping to get children diagnosed by 18 months to give them a head start on treatment.
The 2010 numbers are being gathered now, but won't be available for another two years.