Initial unemployment claims soared 78,000 to 439,000 in the week ended November 10, the highest reading since April.
Continuing claims rose 171,000 to 3.334 million in the week ended Nov. 3, up from 3.163 in the prior week.
The Labor Department said the numbers reflect the effects of Hurricane Sandy in several states.
Unadjusted claims rose 104,548, with a large number in the mid-Atlantic region, which were hit by Sandy.
Economists polled by Thomson Reuters expected 375,000 initial claims and 3.230 million continuing claims.