The IBGE's broad measure of consumer price inflation rose to 4.93pc , the highest since February 2017, and up from 4.71pc in the month to mid-April.
The median forecast in a Reuters poll of economists was for a rise to 4.98pc .
The monthly rate of inflation fell to 0.35pc from 0.72pc , lower than the 0.42pc economists had expected.
"The softer-than-expected mid-month inflation figure for May, of 4.9pc , suggests that the headline rate has now peaked," wrote William Jackson, chief emerging market economist at Capital Economics, in a note to clients.
"We think it will fall back below the central bank's target in the coming months. Copom will be under no pressure to raise interest rates for the foreseeable future," he said, referring to the central bank's rate-setting committee.
The minutes from Copom's last meeting earlier this month showed policymakers were slightly less confident in their previous statements that inflation would peak around April-May before drifting back towards 4.25pc target by the end of the year.
On Wednesday, the government raised its 2019, inflation target to 4.1pc from 3.8pc .
According to IBGE, the price of household goods fell 0.36pc on the month, communications dipped 0.04pc , while food and drink and education costs were unchanged.
Health and personal care goods and transport costs showed the biggest increases on the month, rising 1.0pc and 0.65pc , respectively.