BEIJING, June 27 (Reuters) - Profits of Chinese industrial companies rose 3.7 percent in May from a year earlier, slowing from April's pace and adding to concerns about the health of the world's second-largest economy.

Profits in May rose to 537.2 billion yuan ($81.21 billion), the statistics bureau said on Monday. Profits in the mining sector fell 93.8 percent from a year earlier, the bureau said.

In the first five months of this year, profits rose 6.4 percent compared with the same period last year, the National Bureau of Statistics said on its website.

Industrial profits in January-April rose 6.5 percent from a year earlier, with April up 4.2 percent.

Chinese industrial firms' debt at the end of May was 4.9 percent higher than at the same point last year.

The data covers large enterprises with annual revenue of more than 20 million yuan from their main operations.

($1 = 6.6150 Chinese yuan renminbi) (Reporting By Winni Zhou and Nicholas Heath; Editing by Kim Coghill)