Net loss was £968m in Q1, up from £459m in the same period last year. The bank said that excluding the one-off payment to the government, which will enable it to restart paying dividends to private shareholders, it would have posted a profit of £225m.
The bank reported a profit before tax of £421m for the quarter, compared to £37m in the year-ago period.
Total income declined 13% to £3.06bn in the quarter, from £3.52bn in the same period a year earlier.
Operating expenses were £2.42bn in the quarter, from £3.61bn in the first quarter of 2015.
The bank said income was stable compared with across its core personal & business banking (PBB) and commercial & private banking (CPB) franchises.
Core PBB and CPB net loans and advances increased by 15% on an annualized basis with better growth in both the mortgage and commercial businesses.
RBS chief executive Ross McEwan said: "Today’s results show the strength and resilience of the bank we are fast becoming.
"This bank has great brands and great market positions and piece-by-piece we are building a solidly performing, profitable bank doing great things for customers and returning value for shareholders."
Image: RBS Gogarburn building. Photo: courtesy of Royal Bank of Scotland.