Thousands of people have died from radiation and millions more in the region have suffered health problems.
The mood was particularly sombre in Belarus - where 70% of the radiation fell - and in Ukraine where President Leonid Kuchma led a remembrance ceremony in the capital Kiev.
Thousands of people have died from radiation and millions more in the region have suffered health problems.
"Maybe hundreds of years will pass before the Belarussian people have finally got rid of the consequences of the Chernobyl disaster," deputy emergencies minister Enver Baryew told Belarussian radio
In Moscow the media also traded some grim statistics.
Double disaster
"On 26 April 1986 the word Chernobyl burst into history in a radioactive cloud," the Russian daily Izvestiya said.
"Today it is a town best forgotten. It will remain hazardous for another 24,000 years," it added.
Many newspapers and radio and TV broadcasts focused on the continuing damage to the economies of Ukraine and Belarus.
Every year 20% of Belarus's state budget and 10% of Ukraine's is spent on dealing with the aftermath of Chernobyl, Russian Public TV said.
The TV noted that this is the first anniversary since the Chernobyl plant was finally closed last December and that this year's anniversary was a "double disaster".
There is no work and no welfare programme for the employees who with their families number more than 20,000.
Ghost town
One of the more poignant reports was shown on Russian NTV television whose reporter went to the "dead" town of Pripyat, 7km north of Chernobyl.
He described Pripyat as what towns will probably look like "after mankind vanishes from the face of the earth."
"There are no people here, not a single living soul," he said.
The TV showed pictures of a fairground which was due to open just after the accident. "No child has ever ridden on the merry-go-round here," he said.
Cover-up
Thursday's media coverage is in stark contrast to the reporting at the time. The first terse report came two days after the accident and was the fourth item in Moscow Radio's evening news bulletin.
The initial media cover-up of the scale of the accident, which happened a year after Mikhail Gorbachev came to power, helped give rise to the programme of Glasnost (Openness) and Perestroika (Reconstruction) which led ultimately to the collapse of the Soviet Union.
Russian Public TV regretted that many of the pledges of financial assistance made by the West had not been carried out.
Candles will be lit and speeches made about this "black day", but Ukraine still faced the problem on its own.
"Tomorrow the problem of Chernobyl will be forgotten once again - until the next anniversary," the TV said.