"Are we alone in the universe?" is the fundamental question of mankind. To search for the life signaturesin the universe, there have been a lot of researches and space explorations, especially in our solar system. In this review paper, we introduce the de nition and characteristics of the \biosignature". The currentsituations and future plans for searching for biosignatures in our solar system are reviewed, especially atVenus, Mars, and Ocean Worlds such as Europa and Enceladus where life signatures are more likely toexist than in other places in the solar system. Finally, we discuss the opportunities and strategies for theKorean scienti c society to participate in searching for biosignatures in the solar system.