The financier saw the amount of money it made decline to a level of Â£644 million ($1.03 billion) during this three-month timeframe, which represents a dip of 21 per cent on the Â£820 million recorded in the second quarter.
With this in mind, the lender admitted in a statement released along with the figures that it may now struggle to meet some of its short-term financial targets set earlier in the year.
Because of the fact the global economic recovery is being stunted by issues such as the eurozone crisis, the bank noted it will have to "reassess our assumptions".
"The attainment of some of our medium-term financial targets, principally with regard to income-related metrics, may be delayed to beyond 2014," it added.
Recently, Barclays - one of Britain's other big four banks - revealed its profits rose by five per cent in quarter three.
By Claire Archer