BP dropped to a loss of $ 351 million in the third quarter after lower oil and gas prices, a major hurricane and large one-off charges related to the sale of parts of the company took their toll.
The loss in the three months to the end of September compares with a profit of $ 3.09 billion (£ 2.37 billion) in the same period last year.
Excluding one-off charges, profits still fell more than 40 percent, although performance exceeded market expectations.
Shares fell about 1% at the start of trading.
Chief Executive Bob Dudley said: "BP delivered strong operating cash flow and underlying earnings in a quarter that saw lower oil and gas prices and significant hurricane impacts."
The UK-based oil giant – whose shares are a staple of many pension funds – said production levels were hit by the impact of Hurricane Barry on operations in the Gulf of Mexico.
Lower prices also affected, with Brent oil barrel at $ 62 in the period, compared to $ 69 in the second quarter and $ 75 in the third quarter last year.
Hurricane Barry affected Gulf of Mexico oil production
Meanwhile, BP has assumed an accounting charge of $ 3.32 billion (£ 2.55 billion), largely related to the disposal of US gas assets and the sale of its Alaska business.
The group had already warned investors earlier this month that it expected to receive a multi-billion dollar blow to the deals.
The results came after BP announced that Dudley would step down as chief executive next year after a decade in charge.
He will be replaced by Bernard Looney, who currently heads the company's upstream division – covering exploration and production.
CMC Markets chief market analyst Michael Hewson said: "Today's Q3 figures are not expected to come close to levels seen in Q2 results given the fall in oil prices since then.
"However, they still show a more agile and more efficient company than it was a decade ago."