Sustainability has been an emerging issue for years in the economy and agriculture. Making agriculture sustainable has become so essential that it has become part of the Common Agricultural Policy (CAP). However, producers ultimately decide individually the practices they implement. This is why farmers play a central role in ensuring a sustainable agricultural system, which results from farmers’ knowledge and expectations. Although numerous studies address sustainability issues, little is known about farmers’ knowledge and implementation of sustainable practices at different types of farms, especially in central and eastern Europe. This study aimed to determine Polish farmers’ awareness of sustainability with regards to animal and crop production. This paper also shows how farmers value the advantages arising from sustainable production. The study was carried out among 300 farms classified by type (dairy, beef cattle, pork, and crop production). The research instrument used was a questionnaire, with the Likert scale. The results show that dairy farmers and pork farmers declared higher knowledge and better implement sustainable practices than other farmers. The producers’ views on the benefits coming from sustainable agriculture varied. However, the two most significant advantages were recognized—the protection of water against pollution and the reduction of greenhouse gas emissions.