The deal with the Irish-based firm would have created the world's largest pharmaceutical company.
Pfizer said in a statement the two companies "terminated by mutual agreement" plans to merge.
"Pfizer approached this transaction from a position of strength and viewed the potential combination as an accelerator of existing strategies," said company chairman and CEO Ian Read.
Pfizer also agreed to pay Allergan USD 150 million to reimburse its expenses linked to the planned merger.
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The New York-based pharmaceutical giant said it remains on track to report its 2016 first quarter earnings on May 3.
For all of 2015, Pfizer reported earnings of USD 7.7 billion, down 15.2 per cent from 2014. Revenues dipped 1.5 per cent to USD 48.9 billion.
Allergan CEO Brent Saunders said in a separate statement that while he is "disappointed" that the merger will not proceed, his company is nevertheless "poised to deliver strong, sustainable growth built on a set of powerful attributes.