The Canadian company made a net loss for the three months to 3 March of $125m (£78m), compared with a profit of $934m a year earlier.
Revenues fell to $4.2bn from $5.2bn.
The firm also suggested it would refocus on the corporate market rather than on individual consumers.
Shipments of BlackBerry smartphones in the quarter fell to 11.1 million, down 21% from the previous three-month period.
Shipments of the company's PlayBook tablets hit 500,000, largely due to substantial discounting.
For the full financial year, the company made a net profit of $1.2bn, down from $3.4bn in the previous year."