Patents enable enterprises to monopolize the innovation by prohibiting the usage of other organizations and to gain benefit in economy. However, enterprises can exercise the monopoly rights of innovations only when the applications pass the examination and are granted by the patent offices. During the examination periods, enterprises are uncertain about the legal positions of applications, which carry the uncertainty in financial and strategic planning. Therefore, the factors which might affect the durations provide useful information for enterprises on reducing the uncertainty in strategic and financial planning. In previous studies, the conclusions considering the affecting factors and their affecting directions are inconsistent, which implies that the factors and their affecting directions vary with the technology fields and patent offices. As a result, this study focuses on studying the patents of the United States Patent and Trademark Office and investigates the factors which might affect the examination durations of biotechnology patents granted from 2000 to 2009 for Taiwan and South Korea. This study examines three groups of determinants: indicators representing patent value, applicant characteristics and determinants affecting the complexities of the examination tasks. Based on the survival analysis, the results show that in the examination durations of the biotechnology patents there are no significant difference between Taiwan and Korea. Moreover, the higher value patents have significantly shorter examination durations. The basic research patents and the patents with wider technology fields have significantly longer examination durations than applied research patents and those with narrower technology fields. Finally, this study discusses the directions and sizes of the affecting factors of examination durations for strategic planning.