Rosenft's staff has swelled in recent years, growing at a steady clip after the company paid more than $50 billion last year to take on TNK-BP, a former joint venture between Russian billionaires and British energy company BP.
Russian business daily Kommersant said as many as 1,000 employees could lose their jobs as early as October as part of a cost-saving initiative.
Rosneft is the target of Western economic sanctions imposed in response to Russian policies in eastern Ukraine, where pro-Russian separatists are gaining a foothold. Igor Sechin, its chief executive officer, is also the target of punitive economic measures.
Sechin in August asked the Kremlin to use a national welfare fund to support its growing debt. The company's total production, meanwhile, is down to its lowest level in more than a year.
Rosneft recently secured deals to work alongside Norwegian energy company Statoil. Norway and Russia are the top oil and gas suppliers to the European market, though Statoil said recently sanctions are complicating its relationship with Rosneft.
In July, Sechin said his company was braced for "volatility."