A lawyer for the farmers, Scott Powell, said the jury decided on the judgment after less than two hours of deliberations Thursday in Lonoke County.
The farmers claimed an experimental rice strain developed by Bayer called Liberty Link was allowed to make its way into the stream of commercially marketed rice. Liberty Link was developed to withstand a popular herbicide that kills weeds in the fields.
The suit claimed rice prices were hurt after the contamination was announced in August 2006.
Bayer CropScience is a subsidiary of the German chemical giant that makes aspirin.