Yoani Sanchez had hoped to go to Columbia University for a Wednesday ceremony to receive her Maria Moors Cabot Prize, the oldest international award in journalism.
"Immigration just confirmed that I remain prohibited from leaving the country," she posted on her "Generation Y" blog.
There was no confirmation from the government, but Cuban authorities almost never comment on such matters.
Sanchez's husband, Reynaldo Escobar, who uses his own blog to provide searing criticism of everyday life in Cuba, said in a phone interview that his wife spent the morning discussing her travel request with immigration officials, then posted word of the denial.
In May, Cuban authorities denied Sanchez permission to fly to Madrid to accept the Ortega y Gasset Prize in digital journalism for creating Generation Y, which gets more than 1 million hits a month. Around the same time, Time magazine deemed Sanchez one of the world's 100 most influential people.
In initially announcing the winners in July, Columbia said it was extending Sanchez a "special citation for journalistic excellence."
Sanchez uses Generation Y, started in April 2007, to offer simple but compelling insights into modern Cuba and isn't afraid to criticize the country's totalitarian system, its poverty or the chronically low morale and disillusionment many of its citizens struggle to overcome.
She is one of the few Cubans who dares denounce Cuba's single-party government so openly, though she enjoys more of a following off the island than on it. Internet access to the blog is often blocked in Cuba and Sanchez blames the government, which has refused to comment.