Anurans generally use auditory, chemical and visual signals for species and sex recognition (Wells, 2007). Several studies on sympatric anurans that reproduce synchronously have concluded that differences in the mating call can serve as an important reproductive isolation mechanism (Blair, 1964; Duellman, 1967; Crump, 1971; Höld, 1977), however the advertisement call of a male can be masked by a noisy environment or by the calls of other species, which may lead to interspecific amplexus (Shahrudin, 2016). Other situations, including overlapping in reproductive period, low female availability, confusion of chemical signals, low male selectivity, and explosive breeding behavior may also result in interspecific amplexus (Pearl et al., 2005; Wogel et al., 2005; Mollov et al., 2010; Machado and Bernarde, 2011; Vivek et al., 2014). Smilisca sila Duellman and Trueb 1966, is a Hylid frog distributed from Pacific versant from southern Costa Rica to eastern Panama, and on the Atlantic versant from central Panama to northern Colombia and the middle Magdalena Valley (Köhler, 2011). This species generally breeds during the dry season (January to April), and males of this species call at night along streams, but they do not form dense choruses (da Silva Nunes, 1988). However, at high elevations they may sometimes breed during the rainy season (Duellman and Trueb, 1966). Craugastor fitzingeri (Schmidt, 1857) is a direct developing frog of the Craugastoridae family, distributed from northeastern Honduras to northwestern Colombia (Köhler, 2011). Both sexes are frequently found at night in the understory vegetation 0.5 to 1.6 m above ground often along forest edges. Males usually vocalize from elevated spots on stumps, fallen logs, and low vegetation. Even though this species is commonly observed along the margins of stream courses, and may avoid capture by jumping into the water and hiding on the bottom, it is not a riparian species (Savage, 2002). Strabomantis bufoniformis (Boulenger 1896), is a direct developing frog also from the Craugastoridae family (Padial et al., 2014) distributed on the Atlantic versant from extreme southern Costa Rica to western Colombia (Köhler, 2011). It is a nocturnal, riparian, primary forest species of lowland moist and wet forest. Herein we report two field observations of interspecific amplexus involving these species. The first was recorded on 22 November 2013 at 18:48 h in a stream (9.133333° N, -78.885556° W, Datum WGS 84; elevation 100 m,) in Plan Bonito, Chepo district, Panama province where a multiple amplexus was observed between an adult male of Smilisca sila and an adult male of Strabomantis bufoniformis also in amplexus with a female of same species (Figure 1A). The second observation was on 11 January 2016 at 2048 h, during a field work in a stream (8.956889° N, -78.582583° W, Datum WGS 84; elevation 377 m) in the town of San José, district of Chepo, province of Panama. Here an adult male of Herpetology Notes, volume 11: 167-169 (2018) (published online on 10 February 2018) Two interspecific amplexus of Smilisca sila (Hylidae) with Strabomantis bufoniformis and Craugastor fitzingeri (Craugastoridae) Ángel Sosa-Bartuano 1,2, *, Yostin Jesús Añino Ramos 2,3 , Víctor Martínez Cortés 5,6 ; Rogemif Daniel Fuentes 4 and Humberto Fossatti 6 1 Museo de Vertebrados de la Universidad de Panamá, Campus Octavio Méndez Pereira, Ciudad de Panamá, Panama. 2 Red Mesoamericana y del Caribe para la Conservación de Anfibios y Reptiles (Red MesoHerp). 3 Museo de Invertebrados G. B. Fairchild de la Universidad de Panamá, Campus Octavio Méndez Pereira, Ciudad de Panamá, Panama. 4 Los Naturalistas, P.O. Box 0426-01459, David, Chiriquí, Panama. 5 Departamento de Zoología, Escuela de Biología, Campus Octavio Méndez Pereira, Universidad de Panamá, Ciudad de Panamá, Panama. 6 Centro para Investigaciones y Respuestas en Ofidismo, Campus Octavio Méndez Pereira, Universidad de Panamá, Ciudad de Panamá, Panama. * Corresponding author: asosa2983@gmail.com