This paper contains a synopsis of the genus Phrynopus in Bolivia, including the description of twelve new species. With seventeen species currently known, the genus has a much higher diversity in Bolivia than previously expected. Whereas intraspecific variation is evident only in color pattern, interspecific variation is noticeable in size, robustness, shape of head, relative lengths of extremities and digits, and skin texture. However, some species are quite similar in appearance and would be difficult to identify in the field were it not for their extremely restricted distributions. The genus Phrynopus has an amazing radiation and its species diversity has been severely underestimated.