| Pro | Alexander | Logachev | Soviet Senior Lieutenant. |
| | Vlaskin | | Sergeant. |
| | | | Part 1 |
| 1 | Viktor | Brukhanov | Director of Chernobyl Atomic Energy Station. |
| | Neporozhny | | Minister. |
| | Vladimir | Scherbitsky | Leader of
Ukrainian Communist Party. |
| | Valentina | Brukhanov | Viktor's wife. |
| | Lilia | Brukhanov | Viktor's daughter. |
| | Nikolai | Slichenko | The gypsy superstar. |
| | Leonid | Brezhnev | General Secretary of the Communist Party of The Soviet Union. |
| | Mikhail | Gorbachev | The new leader of Soviet Union. |
| | Ronald | Reagan | U.S. President. |
| | Nikolai | Fomin | Viktor's principal deputy. |
| 2 | Albert | Einstein | A well-known physicist and theorist. |
| | Alexander | Litvienko | FSB agent. |
| | Thomas | Edison | A well-known inventor. |
| | Harry | Daghlian Jr. | A physicist on the Manhattan Project. |
| | Igor | Kurchatov | Father of the bomb. |
| | Lavrenty | Beria | Head of the NKVD. |
| | Nikita | Khrushchev | The newly appointed Soviet Premier. |
| | Paul | Josephson | A historian. |
| | Anatoly | Alexandrov | Director of Kurchatov Institute. |
| | Efim | Slavsky | Chief of Ministry of Medium Maching Building. |
| 3 | Alexander | Yuvchenko | Senior Mechanical Engineer. |
| | Kirill | | Yuvchenko's son. |
| | Natalia | Yuvchenko | Yuvchenko's wife. |
| | Sasha | Korol | A nuclear Engineer. |
| | Leonid | Toptunov | Korol's colleague. |
| | Boris | Stolyachuk | Senior Unit Control Engineer. |
| | Alexander | Akimov | Shift Foreman. |
| | Ivan | | One of the Third Watch men. |
| | Leonid | | One of the Third Watch men. |
| | Grigori | Khmel | One of the Third Watch men. |
| | Vladimir | Pravik | Third Watch commander. |
| 4 | Nikolai | Dollezhal | NIKIET's director. |
| | Nikolai | Steinberg | Chief of turbine department for units 3 and 4. |
| | Jimmy | Carter | The President. |
| | Valery | Legasov | Aleksandrov Immediate Deputy. |
| | Vitali | Sklyarov | Ukranian Minister of Energy and Electrification. |
| 5 | Anatoly | Dyatlov | Control Room 4 deputy chief engineer. |
| | Gennadi | Metlenko | Head of the team of Electrical Engineers. |
| | Valery | Khodemchuk | Senior Coolant Pump Operator. |
| | Igor | Keshenbaum | Senior Turbine Control Operator. |
| | Anatoly | Kurguz | Former Nuclear Submariner. |
| | Yuri | Tregub | Unit Four's reactor control engineer. |
| 6 | Pravik | | A firefighter. |
| | Alexander | Petrovsky | Sergeant. |
| | Anatoly | Zakharov | Fire Station's party secretary. |
| | Viktor | Proskuryakow | A trainee reactor control engineer. |
| | Alexander | Kudryavtsev | A trainee reactor control engineer. |
| | Viktor | Degtyarenko | A Coolant Pump Operator. |
| | Shavrey | | A firefighter. |
| | Piotr | Khmel | Chief of the First Watch. |
| | Valery | Perovozchenko | Yuvchenko's immediate boss. |
| | Razim | Davlebayev | Deputy section chief. |
| | Viktor | Kibenok | Head of the Third Watch fire station. |
| | Vasily | Ignatenko | Firefighter. |
| | Leonid | Telyatnikov | Brigade's chief station 2 (Chernobyl Plant). |
| | Serafim | Vorobyev | Head of plant civil defense. |
| 7 | Georgie | Kopchinsky | Deputy chief engineer in Chernobyl. |
| | Nikolai | Ryzhkov | The Soviet Prime Minister. |
| | Vladimir | Marin | The Communist Party's nuclear chief. |
| | Anatoly | Mayorets | USSR energy minsiter. |
| | Alexander | Iyashko | Chairman of the council of ministers. |
| | Evgeny | Velikhov | A physicist. Leasov's old rival. |
| | Vladimir | Malomuzh | Deputy head of the party for the entie Kiev region. |
| | Boris | Scherbina | Deputy chairman of the Soviet council of ministers. |
| | Alexander | Meshkov | Slavsky's deputy. |
| | Boris | Prushinsky | Chief Engineer of Soyuzatomenergo. |
| | Boris | Ivanov | Deputy Commander of all civil defense forces in USSR. |
| 8 | Veniamin | Prianichnikov | Head of training in plany nuclear safety. |
| | Maria | Boyachuk | Secretary from Ispolkum. |
| | Maria | Protsenko | Chief Architect of Pripyat. |
| 9 | Vladimir | Dolgikh | The central committee secretary. |
| | Vladimir | Pikalov | Commander of the Soviet Army chemical troops. |
| | Nikolai | Antoshkin | Chief of Staff of the Soviet Air Defense Forces. |
| 10 | Yegor | Ligachev | Chief of Ideology for Communist Party. |
| | Ivan | Silayev | Former Soviet Minister of Aviation Industry. |
| | Viktor | Chebrikov | Head of the KGB. |
| 12 | Hans | Blix | IAEA Director General. |
| | Morris | Rosen | Director of Nuclear Safety. |
| | Boris | Baranov | Chief shift manager for the plant hospital 6 Moscow. |
| | Alexander | Baranov | Head of Hematology. |
| | Robert | Gale | A Hematologist at UCLA. |
| | Vera | Toptunov | Leonid's mother. |
| | Armand | Hammer | A philanthropist and art collector. |
| 15 | Gennadi | Shasharin | Mayorets's deputy responsible for nuclear matters. |
| 16 | Alexander | Borovoi | Head of the neutrino laboratory. |
| | Tarakanov | | Deputy Commander of the USSR's civil defense forces. |
