The year 1945:
On 12 May 1945 in Belgrade, the Yugoslav government adopted a decision on the establishment of Jugopetrol, a state-owned petroleum company based in Belgrade, which in the same year began to form branches across the country; its Ljubljana subsidiary was founded in June. The Maribor refinery was launched in October 1945, having taken over the assets of the pre-war company “Motor Oil” Maribor. On 21 December 1945 the Lendava Oil Company was established, superseding the pre-war company “Medjimurska petrolejska d.d. Zagreb” and since 1947 operating under the name “Proizvodnja nafte Dolnja Lendava”.

The year 1946:
On 6 December 1946 the government adopted a law on the nationalisation of private companies, which also applied to Standard and Shell, though these two companies had only minor assets in Slovenia. In the branches where these assets were substantial, the Slovenian subsidiary of Jugopetrol appointed directors. At the end of 1946 the Slovenian branch of Jugopetrol had 221 employees.

The year 1947:
On 12 April 1947 Jugopetrol Beograd was terminated, and at the same time Jugopetrol Ljubljana was founded in Slovenia. By the end of 1947 Petrol was selling fuel at nine service stations across Slovenia.

The year 1948:
In November 1948 the first stage of the new storage facility in Zalog was completed, in addition to nine petroleum storage facilities and ten service stations operated by Petrol.

The year 1950:
In 1950 the company had 213 employees and started to build new storage facilities in Postojna, Brežice and Kočevje. That year Jugopetrol Ljubljana already had 13 operating service stations and sold some 56,000 tonnes of oil derivatives. On 22 February 1951 Jugopetrol Ljubljana adopted its first company rules. In October 1952 Jugopetrol Ljubljana took over and re-launched the Maribor refinery, which had not been operational since 1949.