By market open, shares had surged 24.7% to $24.69.
The provider of weight-management services earned 31 cents a share over the three months to March, 22 cents higher than analysts surveyed by Thomson Reuters forecast.
"We are encouraged by the progress we are making on our transformation plan, but there is still a great deal of work to do," said CEO Jim Chambers in a statement.
Revenue slid 15.9% year over year to $409.4 million, beating expectations by $10.2 million.
Management revised its full-year earnings guidance to between $1.45 and $1.70 a share. Analysts had expected $1.40 a share.
TheStreet Ratings team rates WEIGHT WATCHERS INTL INC as a Hold with a ratings score of C. TheStreet Ratings Team has this to say about their recommendation:
"We rate WEIGHT WATCHERS INTL INC (WTW) a HOLD. The primary factors that have impacted our rating are mixed -- some indicating strength, some showing weaknesses, with little evidence to justify the expectation of either a positive or negative performance for this stock relative to most other stocks. Among the primary strengths of the company is its expanding profit margins over time. At the same time, however, we also find weaknesses including feeble growth in the company's earnings per share, deteriorating net income and weak operating cash flow."