In a deal that would combine two generic drugmakers that recently left the U.S. for Europe, Mylan says it wants to buy Perrigo for $205 per share, or $28.86 billion.
Mylan's cash-and-stock offer comes at a premium of 24 percent to the latest closing price for Perrigo shares.
It says the combined company would be a leader in specialty drugs, generic medicines, and over-the-counter and nutritional products.
Mylan says it delivered a proposal to Perrigo on Monday. Perrigo did not immediately respond to a request for comment.
Mylan NV relocated to the Netherlands in March after buying a unit of Abbott Laboratories for $5.3 billion. Perrigo Co. moved to Ireland in December 2013 after it bought Elan Corp. for $8.6 billion.
The moves slashed both companies' tax bills.