Blaming the impact of the March disasters and a weaker electronics business environment, Sony said it slipped to a 15.5 billion yen ($191 million) net loss in April-June, the quarter in which it also suffered a massive hacking attack on its online networks.
The figure compared to a 25.7 billion yen profit in the same period a year ago.
It lowered its May forecast for an 80 billion yen net profit in the current fiscal year ending March 2012 to 60 billion yen.
It also revised its sales forecast lower by 4 per cent to 7.2 trillion yen.
The Japanese electronics and entertainment giant last year posted its third annual loss in a row but has forecast a return to the black this year despite a huge attack from hackers.
Sony suffered a net loss of 259.6 billion yen in the year to March, citing a large write-down in deferred tax assets.
The Tokyo-based maker of PlayStation consoles and Bravia television sets was forced to shutter plants in Japan after the quake and tsunami disaster battered supply chains, damaged some facilities and dampened consumer demand.
And it shut down its PlayStation Network and Qriocity services in April after being hit by hackers, and said it could not rule out that millions of credit card numbers may have been compromised. It has since restored its online services.