Mikulski, a Maryland Democrat, is to join a bipartisan group of senators from poultry states in that letter. She said Russia's trade stoppage amounts to "raw protectionism."
Russia banned US poultry imports last winter, saying it didn't want to accept birds processed with chlorine, a chemical companies use in food safety. In the past three years, US poultry exports to Russia have been valued at $800 million.
"Today it will be (problems with) antibiotics. Tomorrow it will be we don't use enough antibiotics," Mikulski said.
The 74-year-old Baltimore senator, is seeking her fifth term in November