It claimed that it's needed to pay special attention to the development of higher education in the region in order to improve the economic and cultural life and science of the country.

On June 2, 1940 a decree of the Central Committee of the Communist Party and the Council of People's Commissars of the Karelo-Finnish SSR "About opening of the Karelian-Finnish State University" was published.

The university was called KFGU in abbreviated form, consisted of 4 faculties: historical and philological, physical and mathematical, biological, geographical and hydrogeological.

The goal of university was preparing a large number of specialists for the national economy and the development of scientific research.

A lot of difficult problems had to be solved connected with the simultaneous building of classrooms, accommodation for teachers and students, purchase of the necessary equipment and appliances, integration of scientific university libraries, the development of work plans and teaching aids.

[3] On September 2, 1940, more than 700 students of all courses began their studying at a young university, 417 people of them were freshmen.

[4] The first school year was coming to an end, students were passing the session making plans for the summer.

In connection with this event on June 28 the general university meeting was held in Petrozavodsk at which the participants expressed their desire to fight against the enemy and to give their strength for the victory over him.

During the first months of the war the students, the members of staff, teachers went to the front, also the rector of the university T. I. Lekhen was among them.

[6] The students and teachers made contribution to the struggle against the enemy not only at the battlefield but also in the rear they worked at the factories, built fortifications.

[7] In spite of the hardships of the war the research activities did not cease, although some research topics have changed: now they were focusing on the needs of defense industry, the tasks of the national economic development of the Northern region and an identifying the reserves for military needs.

For example, scientists-geologists carried out the exploration of mineral resources in the Republic of Komi and the Urals, and the Department of Plant Physiology studied the frost-resisting ability of potato, the acclimatization of tobacco and sugar beets in the North.

[9] Hard time of the Great Patriotic War the university survived with dignity, it didn't stop its activity and on the contrary – it directed all the energies for the victory.

[10] But in spite of everything in the period from 1942 to 1945 years 65 students graduated from the university, among them there were one geographer, three geologists, six mathematicians, 21 biologists, 34 historians and philologists.

To address that problem, the local government in cooperation with USSR Ministry of Higher Education decreed to expand the university's program in various fields, such as heavy industry, civil construction and agriculture.

In 1956, the forest engineering faculty opened a night school branch for the workers and employees of the Onega Tractor Plant.

[12] In 1958, the university's faculties were assigned internship bases, according to the new law of linking the school to daily life.

[12] Because of all these reformations, the university managed to become a source of wide-purpose qualified workforce, the income of new students increased considerably as well as the numbers of professors and lecturers.

[12] In the 1950s and 1960s, extensive scientific research was being conducted within the university, for example, the students and professors of the History and Philology faculty actively participated in archeological, folklorist and linguistic expeditions, gathering valuable information on the history and culture of the native peoples of the republic.

Thanks to the works of some historians, a large number of new documentary sources were unveiled to a wide range of readers.

The STEM field scientists of the university also conducted valuable research and acquired particular results, such as developing methods of separation and analysis of optically active isomers of important biological compounds – amino acids, phosphatides; or studies into the process of destruction of metals and alloys due to material fatigue.

It staged various plays based on the works of A. Ostrovsky, L. Oshanin, A. Arbuzov, B. Brecht, that were warmly welcomed by the viewers.

At the same time, a Finnish dramatical club was created under the supervision of an Honored Artist of USSR and Karelia T. I. Lankinen.

In 1964, the tourist club "Sampo" was founded under the supervision of Y. S. Lanev, to guide hundreds of students into the wild unknown during the years.

[24] PetrSU was one of the first universities that implemented an integrated program of the USSR Ministry of Higher Education called "ICS-university".

To improve the work of the university, the university researchers developed a number of software systems including "Entrant", "Number of students", "Session", "Current control", "Social and political practice," "Graduate student," "Control of decision implementation", and "Human Resources Staff".

[29] In 1987, in the framework of the program aimed at continuous development of education, courses for improve of professional skills were created for leading workers of the national economy.

Relations were established with the universities of the cities of Oulu and Kupio (Finland), Umeå (Sweden), Duluth (United States).

There was an exchange of teachers and students between universities and PetrSU and also joint scientifics researches were conducted.