US health authorities have revealed that one in 68 children has autism, a 30 percent rise over the last estimate released in 2012.
The latest US data from the Centers for Disease Control and Prevention show that the "proportion of children with autism and higher IQ (is) on the rise," said a CDC statement.
Previously, as many as one in 88 US children were known to have autism spectrum disorder, or ASD, a developmental disorder that recent research suggests may originate in the womb.
"This new estimate is roughly 30 percent higher than previous estimates reported in 2012 of 1 in 88 children (11.3 per 1,000 eight year olds) being identified with an autism spectrum disorder," said the CDC.
The findings were based on diagnoses of eight-year-olds at 11 US sites in 2010.
The prevalence of autism varied widely, from one in 175 children in Alabama to one in 45 children in New Jersey.
The data continued to show that autism is five times more common in boys than in girls. In the United States, one in 42 boys is diagnosed with autism, compared to one in 189 girls.
The reasons for the rise were unclear, but the CDC said the criteria used to diagnose autism spectrum disorder and the methods used to collect data have not changed.
The American Academy of Pediatrics issued a statement that said the CDC report shows the "urgent need" for better screening and intervention strategies.
"It's critical that we as a society do not become numb to these numbers," said Susan Hyman, chair of the AAP autism subcommittee.
"They remind us of the work we need to do in educating clinicians and parents in effective interventions for all children, including those with developmental disabilities."