Nearly 26 million in US above the age of 20 have diabetes and more than a quarter or 7 million do not know they have the disease, the Centers for Disease Control and Prevention said.
"These distressing numbers show how important it is to prevent type 2 diabetes and to help those who have diabetes," said Ann Albright, director of the CDC's diabetes translation division.
"We know that a structured lifestyle program that includes losing weight and increasing physical activity can prevent or delay type 2 diabetes," she said in a statement announcing the latest statistics.
Type 2 diabetes accounts for 90 to 95 percent of the cases. The condition arises when the body gradually loses its capacity to produce and use insulin to regulate sugar levels in the blood.
In 2008, 7.8 percent of the US population, or 23.6 million people, had diabetes and 57 million adults were classified as pre-diabetic with higher than normal blood sugar levels, according to a study by the Centers for Disease Control.
The CDC found that the number with diabetes has since climbed to 26 million people and 79 million more are now considered to be pre-diabetic, which increases their risk of heart disease and stroke.
It said that 35 percent of adults age 20 and up in the United States fall into the pre-diabetic category.
The latest CDC statistics indicate that 8.3 percent of Americans of all ages and 11.3 percent age 20 and older are diabetic.
The CDC estimates that around 27 percent of Americans with diabetes, or around seven million, are not aware of it.
Last year, the CDC warned that one in three American adults could be diabetic by 2050 if the current trends persist.
Risk factors for adult diabetes include aging, obesity, heredity, having diabetes during pregnancy, a sedentary lifestyle and race or ethnicity.
Black Americans, Hispanics, Amerindians, indigenous Alaskans and Pacific islanders are the most predisposed to adult diabetes.