Issa is questioning how the commission has spent $8 million so quickly and whether the commission's staff has been sufficiently bipartisan.
"I am troubled by the extensive ties of some of the senior staff at a putatively bipartisan commission to partisan Democrat politics," Issa said.
The commission was created to look into the causes and consequences of the 2008 crisis. Issa was one of the original supporters of the commission, which is due to issue a report by the end of the year. The panel has held a series of high-profile hearings with bank executives, federal regulators and other officials.
The commission's work has come as Congress completed work on sweeping financial overhaul legislation designed to better regulate the financial industry against threats of future crises. President Obama signed the 2,315-page bill into law last week.
Issa is seeking a lengthy list of documents and personnel records by mid-August.