Born on May 31, 1980 in Kharkiv. He graduated from 9th grade of Kharkiv Gymnasium No. 14, and then received a complete secondary education at Kharkiv Evening School of II-III Degrees No. 16.
After studying, he went to work in the food industry. He devoted more than 25 years of his career to the meat processing industry: processing raw materials (meat of cattle, poultry, rabbits) for the production of a wide range of finished products. He worked in the city of Kharkiv. Having moved to the city of Chuguiv in 2007, he continued to work in this field until his mobilization.
From the memories of his younger brother: "In life, Oleg was a "dreamer." He often lived in his dreams, sometimes not even connected with reality. He was distinguished by great kindness, sensitivity and non-maliciousness. Even despite his profession, Oleg, as they say, "couldn't offend a fly." He never made a fuss and knew how to get out of a conflict situation. I never thought that my brother would fight in the assault troops. He didn't even admit to my sister and me that he was a machine gunner. He always said that he was serving in the food unit. When going on assaults where he couldn't get in touch, he always justified himself by saying that there was poor communication. And only after his death did we learn the whole truth.".
Oleg Petrosyants was called up for mobilization on 07.01.2025 by the third department of the Chuguiv RTCC and SP. He served as part of the 225th separate assault regiment as a machine gunner of the 1st assault detachment of the 1st assault platoon of the 2nd assault company of the 2nd assault battalion. The regiment is actively engaged in frontline activities, the regiment's fighters took a direct part in the Kursk operation, acting as a breakthrough unit, participated in battles on the border with the Sumy region, in defensive battles in the Sumy region, while conducting successful operations to liberate and hold settlements in the Sumy region.
Circumstances of death:
In the summer of 2025, the regiment's units successfully cleared and consolidated the settlement of Kindrativka in the Sumy region. But the enemy did not give up the task of capturing the Sumy region, and therefore in the fall of 2025, hostilities continued. Russian troops tried to advance in the Khotyn community, but Ukrainian forces held their defenses. The unit where Oleg Petrosyants served occupied combat positions in the settlement of Kindrativka and its surroundings. At about 15:48 on October 31, 2025, the enemy struck the positions of the defenders with an FPV drone. Oleg Petrosyants received injuries incompatible with life.
Oleg Petrosyants was buried on November 13, 2025 with full military honors in Chuguiv on the Alley of Memory.
The warrior is survived by a younger brother and sister.