1964 – the State Oil and Chemical Industry Committee of the USSR starts to consider the idea of an oil refinery in Lithuania

1966 – start of designing of a refinery to be built in Lithuania

1966 – start of construction of trunk crude oil pipelines in Lithuania

1968 – commissioning of the Birzai Pump Station on the Polotsk – Ventspils crude oil pipeline

June 24, 1970 – a location near Mazeikiai is approved as the site for the refinery

1970 – commissioning of the Polotsk – Ventspils products pipeline crossing Lithuania

1971 – geologists complete studies of the refinery site. Site preparation activities started in autumn with constructing roads and railways

1972 – start of refinery construction work

1979 – completion of the Polotsk – Birzai – Mazeikiai crude oil pipeline

1980 – commissioning of LK-6U Unit (atmospheric rectification, catalytic reforming, distillates hydrotreating, and a gas plant)

1984 – commissioning of the second LK-6U Unit

1989 – commissioning of KT-1/1 Unit (heavy fuel oil vacuum distillation, visbreaking, distillates hydrotreating, catalytic cracking, absorption, and gas fractionation)

1995 – state-owned company Nafta reorganized into joint-stock company Mazeikiu Nafta, with around 90 percent of shares remaining in the government’s hands and the other 10 percent distributed among employees

December 1, 1998 – reorganization of the joint-stock companies Mazeikiu Nafta, Butinges Nafta (operator of the Butinge Terminal), and Naftotiekis (operator of Lithuanian pipelines), with merging the latter two into Mazeikiu Nafta

July 21, 1999 – start of loading operations in the Butinge Terminal

October 29, 1999 – the Lithuanian Government, Mazeikiu Nafta, and Williams International sign an agreement, under which Williams International became a 33-percent owner and operator of Mazeikiu Nafta

2000 – start of a comprehensive refinery modernization program

July 18, 2002 – the Lithuanian Government, Williams International, and YUKOS sign investment agreements, under which YUKOS acquired a 26.85-percent stake in Mazeikiu Nafta

September 19, 2002 – YUKOS acquires from Williams International an additional 26.85 percent stake and associated rights in Mazeikiu Nafta, assuming all rights and obligations of Williams International under the 1999 agreements with the Lithuanian Government including operator rights in Mazeikiu Nafta

Beginning of 2003 - UAB Mazeikiu Nafta Trading House, subsidiary of AB Mazeikiu Nafta, established for marketing Mazeikiu Nafta's products

September 2003 – Isomerization Unit PENEX commissioned

2004 – Rail Car On-spot Loading Facilities commissioned

2005 – start of construction of gasoline hydrotreater

2005 – Mazeikiu Nafta acquires the majority interest in AB Mazeikiu Elektrine (Power Station)

2006 – PKN ORLEN, Polish company, becomes the major shareholder of Mazeikiu Nafta

August 2007 – FCC Gasoline Hydrotreatment Unit commissioned

June 2009 – official opening of the new Hydrogen Generation Unit

September 1, 2009 - Public Company Mazeikiu Nafta changes the name to Public Company ORLEN Lietuva

April 2013 – official opening of the new Sulfur Degassing and Pelletization Unit