The online retail giant had previously refused to register to collect Pennsylvania's 6 percent levy on its orders. But a spokesman said the company reversed itself because a state directive requiring it takes effect Saturday.
"We believe that customers (in Pennsylvania) will continue to come to Amazon because we offer the best prices with or without sales tax," said the spokesman, Scott Stanzel.
The Seattle-based company currently collects sales taxes on orders shipped to six other states - Kansas, Kentucky, North Dakota, New York, Texas and Washington. It plans to add California to the list on Sept. 15, he said.
Stanzel said Amazon believes questions about the taxation of online purchases should be resolved by federal legislation that uniformly gives states that authority. Two bills are pending in Congress, and he says there appears to be growing support for such a law.
The company has been advising Pennsylvania customers about the change in policy if they inquire about it, Stanzel said.
Amazon's reversal was a victory for the state Revenue Department, which contends that existing law requires online retailers to collect the Pennsylvania tax if they have a physical presence - a warehouse, for example - that creates a "nexus" with the state.
Amazon has six fulfillment centers in Pennsylvania - two apiece in Breinigsville in Lehigh County and Carlisle in Cumberland County, and one each in Luzerne and York counties, Stanzel said.
In December, the Revenue Department issued a bulletin to clarify that certain other activities also trigger tax-collection obligations for online companies, such as employing anyone who regularly travels to the state for any purpose related to their business activities.
The department originally gave companies until Feb. 1 to register or face possible actions ranging from audits to criminal prosecution. Officials later decided that deadline was impractical and pushed it to Saturday.
A department spokesman declined to comment on Amazon's decision.