Agricultural researchers and science librarians must understand which research literature databases provide the most comprehensive coverage of agricultural subjects to support their inquiries. Once the domain of a few specialized databases, agricultural research literature is now covered by broad, multidisciplinary databases. The purpose of this study is to determine the most comprehensive database(s) for agricultural literature searching. We compared the coverage of eight bibliographic databases for a range of agricultural sub-topics to determine how much overlap exists and which database(s) best support discovery of agricultural research literature. We found that the multidisciplinary databases provided the most comprehensive coverage, along with one of the agriculture-specific databases. This study will help researchers and librarians determine where to invest their effort and resources when looking to find agricultural research content.