Jobless claims rose by 46,000 in the week, obliterating the 30,000 claim drop a week earlier that put initial benefit claims at a 56-month low.
Last week's total of 339,000 was revised higher to 342,000. The additional 46,000 claims for the current report put total claims at 388,000.
The four-week rolling average came to 365,500, an increase of 750 from the previous week.
The advance number of unadjusted actual first-time jobless benefits claims under state programs totaled 359,048 for the week, an increase of 29,129 from the previous week, the Labor Department said.
There were 357,562 initial benefits claims in the comparable week in 2011, the department's Employment and Training Administration said.