Halliburton said U.S. natural gas drilling helped lift North American sales above the year-earlier level.
"All the upside was North America," said analyst Kurt Hallead of RBC Capital, while margins were "weaker than everybody expected" in the rest of the world.
Halliburton shares fell 0.8 percent to $31.40, giving up an early gain, as weak oil prices weighed down the sector .OSX.
The company said it had hired 1,200 people in the first quarter, after cutting its workforce by 6,000 to 51,000 last year, largely to cater to growing North American demand.
Halliburton expects North American margins to improve more this quarter, as limited natural gas drilling growth is offset by greater oil-targeted activity due to a healthier oil price.
Pricier oil also led to more activity by big exploration and production companies across most international markets outside Latin America, Chief Executive Dave Lesar said.
"I wouldn't point to one particular area as being particularly good or bad," Lesar told analysts on a conference call. "The indications are it should be increasing just about everywhere in the Eastern Hemisphere."
He said he expected a steady resurgence in international activity for the industry in the second half of 2010 and 2011.
He also said there would be plenty of work to do in Iraq, where Halliburton is building a presence, like Schlumberger.
Halliburton's first-quarter net profit fell 46 percent to $206 million, or 23 cents per share, from $378 million, or 42 cents per share, a year earlier.
Excluding a $31 million charge from Venezuela's currency devaluation and a $10 million tax-related charge there, earnings per share were 28 cents. That topped the analysts' average forecast of 25 cents on Thomson Reuters I/B/E/S.
Revenue fell 4 percent to $3.76 billion, as expected.
Lesar called the Latin American results disappointing, citing falling activity in Mexico and delays in new projects.
In Mexico, auditors have urged state oil monopoly Pemex PEMX.UL to slash production estimates at the flagship Chincotepec project, where Halliburton has service contracts.
Halliburton is the first major oil services firm to report results for the latest quarter. Weatherford Ltd is set to do so on Tuesday, followed by Schlumberger on Friday.
Improving cash flow has led to talk of how Halliburton will deploy some of its money. One possibility is acquisitions to expand its range of service offerings, such as its purchase of Boots & Coots announced this month.