IBM's total revenue for the quarter ended March 31 was $24.6 billion, up 8 percent from the same quarter last year, or up 5 percent on a constant currency basis. Net income after one-time charges climbed 10 percent to $2.9 billion, IBM said.

Revenue was up in all geographies, with sales growing 12 percent in the Asia Pacific and 9 percent in the Americas. The recovery in Europe continued to lag behind, with sales up 3 percent for the Europe, Middle East and Africa region.

"On the strength of this performance, we are raising our full-year 2011 operating earnings per share expectations to at least $13.15,” IBM Chairman, President and CEO Sam Palmisano said in a statement.

Revenue from IBM's global technology services increased 6 percent to $9.86 billion, with revenue from global business services up 7 percent to $4.7 billion.

Its hardware sales increased 19 percent to $4 billion. Within that division, IBM's mainframe business continued its recovery, with 41 percent sales growth from a year ago, and its Power systems also did well, with sales of those Unix products up 19 percent, IBM said.