Output inched up by 0.1 percent from the previous months, after falling by 0.3 percent in April, 0.8 percent in March and 0.8 percent in February.
Calculated on a 12-month comparison, however, industrial production was still down by 4.2 percent - the 21st consecutive negative result.
The best performing sectors over the 12-month period were computers and electronic goods, pharmaceuticals and the food and drinks industry, while energy products and consumer goods were sharply down.
Ratings agency Standard and Poor's on Tuesday downgraded Italy's rating by one notch to BBB on worries over its ability to resist the effects of a two-year recession and warned the public deficit could go higher than expected.
Stocks in Milan dipped on Wednesday, with the main index down 0.76 percent.
The International Monetary Fund last week cut its economic forecast for Italy, saying it expected the economy to shrink by 1.8 percent this year.
For 2014, however, the IMF increased its forecast to 0.7-percent growth.