The calling activity and agonistic behavior of Pseudis minuta Günther, 1858 were described based on observations made in the Reserva Biológica do Lami, Porto Alegre municipality, Brazil. Field work included bimonthly surveys in one semipermanent pond, each lasting approximately two days and two nights, from August 2004 to July 2005. Males produced three distinct calls: the advertisement call and two aggressive calls. The dominant frequency of the advertisement call was not correlated with the mass or the snout-vent length of the recorded males. We observed two agonistic interactions between males: one involved acoustic interaction, and the other, acoustic and physical interactions. Calling activity was primarily nocturnal, and occasionally diurnal, with peak at about 2300 h. The number of calling males varied significantly through the year with a peak in September.