Analysts predict the country's four major banks will post a sixth consecutive year of record profits with combined earnings rising more than 5 percent, thanks to tighter cost controls, less exposure to bad debt and a booming property market. Other banks report half-yearly results in May.
CBA said its loan impairment expense fell to A$457 million for the six months to Dec. 31, from A$616 million a year earlier.
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"It's similar to ANZ, asset quality is still improving," said Bell Potter banking analyst TS Lim.
Analysts polled by Thomson Reuters had, on average, expected CBA to post earnings of A$4.15 billion. Cash earnings, which exclude one-offs and non-cash accounting items, are closely watched by investors.
The result puts CBA on track to reach analysts' forecast net profit of A$8.76 billion for the full year, which would be a record. But CBA gave a subdued forecast of economic conditions, with chief executive officer Ian Narev saying volatility in global markets was suppressing business confidence.
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"There is little real evidence, so far, of a meaningful increase in investment in the rest of the non-resource sector of the Australian economy, other than in housing," Narev said.
"We continue to assume that any improvements in economic activity in the next year will be gradual rather than dramatic."
The bank's overall net interest income grew by 8 percent to A$7.44 billion.
But it said its net interest margin shrank from the prior six months because of competition and lower cash rates. It declared an interim dividend of A$1.83 fully franked, up 12 percent on the prior interim dividend.