Spiegel reporter and NSA expert Holgar Stark said it was highly likely that the IAEA headquarters in Vienna, as well as the Russian, Iranian and North Korean embassies in the Austrian capital, were bugged as well.
The "foreign policy goals" of the OSCE are of particular interest to the NSA, the Austrian daily Presse said.
The current crisis in Ukraine has revived the prominence of the OSCE - previously it became important as a connection between the east and west during the Cold War.
The US embassy in Vienna has not commented.
Stark has access to documents provided by the US whistle-blower Edward Snowden, and is the co-author of the book The NSA Complex.
The reporter said that the spying order for the OSCE was "presidentially approved". He added that one could assume NSA agents were also present in Vienna.
In addition, he also asserted that there was a secret document called the President's Daily Brief, which gave US President Barack Obama regular updates on controversial information from around the world, including from Vienna.