| Year | Detail |
| 1953 |
Eni, Ente Nazionale Idrocarburi (national hydrocarbon authority), was founded. |
| 1954 |
Eni acquired a 51.025% stake in Anic. |
| 1955 |
Joint study and research laboratories in San Donato Milanese was inaugurated. |
| 1960 |
Eni signed an agreement with Oleodotti Internazionali. |
| 1965 |
Eni was granted a licence by the Danish government to carry out prospecting operations in Greenland. |
| 1971 |
Eni set up Tecneco, an engineering company operating in the environment protection sector. |
| 1977 |
Eni signed an agreement with the Brazilian Getulio Vargas foundation. |
| 1980 |
The company has acquired Chimica e Fibra del Tirso. |
| 1981 |
Eni set up Agip Carbone, a company dealing with all types of operations connected to the integrated cycle of fuel. |
| 1985 |
Eni International Bank ltd was set up. |
| 1989 |
Enimont Spa was set up to run the Italian chemical sector. |
| 1991 |
Eni inaugurated its new headquarters in San Donato Milanese. |
| 1996 |
Acquired Sun Oil Britain Ltd. |
| 1999 |
Eni signed an agreement with the National Iranian Oil Company. |
| 2000 |
Eni became part of the Galp corp. |
| 2002 |
The Gas & Power (G&P) Division began operatin. |
| 2005 |
Eni purchased 90% of the shares in Sarcis S.P.A. |
| 2009 |
Eni completes the acquisition of Distrigas in Belgium. |
| 2011 |
Eni signs a Memorandum of Understanding with PetroChina. |
| 2014 |
Eni Corporate Research Center for Non-conventional Energy becomes Renewable Energy and Environmental R&D Center. |
| 2019 |
Eni enters the Australian renewable energy market. |
| 2022 |
Eni and the Republic of Mozambique agree on joint initiatives to produce agro-feedstock for biofuels. |