The company based in Waterloo, Ontario, had posted a profit of USD 98 million in the December-February quarter a year earlier and a USD 4.4 billion loss in September-November.
Revenue declined 64 per cent to USD 976 million in December-February from USD 2.7 billion in the same quarter a year ago, it said in a statement. Revenue fell 18 per cent from USD 1.2 billion in the third quarter.
"We have significantly streamlined operations, allowing us to reach our expense reduction target one quarter ahead of schedule," Chief Executive Officer John Chen said.
"I am very pleased with our progress and execution in fiscal Q4 against the strategy we laid out three months ago," said Chen, who took over in November.
The firm sold about 3.4 million smartphones, including shipments made and recognised prior to the fourth quarter, which reduced the company's inventory in channel, it said.
"Of the BlackBerry smartphones sold through to end customers in the fourth quarter, approximately 2.3 million were BlackBerry 7 devices," the firm added.
Total of cash, cash equivalents, short-term and long-term investments was about USD 2.7 billion on March 1, from USD 3.2 billion at the end of the previous quarter.
During the quarter, BlackBerry incurred charges related to its Cost Optimization and Resource Efficiency (CORE) programme of about USD 148 million pre-tax or USD 105 million after tax.
Substantially all of the pre-tax charges were related to one-time employee termination benefits, facilities and manufacturing costs.
It started the CORE programme in 2012 to streamline operations and increase efficiency, including optimising manufacturing, outsource global repair services and reduce its workforce.
BlackBerry follows a March-February financial year and the results are based on US Generally Accepted Accounting Principles.
For the full financial year, the net loss widened to USD 5.9 billion from USD 646 million in the previous year while revenue fell 38 per cent to USD 6.8 billion.