AWEA said Exelon had been acting in a way that was "inconsistent with our mission and our purpose" and had been "leading an organised campaign against the industry's number one priority" [the PTC].
Exelon, the US's largest owner of nuclear power, distributes electricity to 5.4 million customers in northern Illinois and southeastern Pennsylvania.
The company became a major player in the US wind industry in 2010 when it bought John Deere Renewables for $860 million. The deal gave Exelon its first 735MW of wind capacity, spread across 36 projects in eight states.
There have been reports in the US press that the low price of wind energy had been detrimental to Exelon's bottom line.
Last month, Exelon chief executive Christopher Crane come out openly against the PTC extension. He said: "The [production tax credit] has been in place since 1992, I believe. And I think that's enough time to jump-start an industry, 20 years. So we've made it known, even as a wind company, that it should be stopped."
In a statement on AWEA's decision, Exelon said: "It is unfortunate that the American Wind Energy Association (AWEA) has voted to end Exelon's membership in the organization. Exelon supports wind energy and is one of the largest wind energy producers in the country."