Echolocation is characteristic of bats of the suborder Microchiroptera. Though recent studies of echolocation calis in Latin America have generated significant advances in knowledge about distribution, habitat use and ecology of bats, the recording and analysis of bat calis is barely known in Chile. As a first step in studies on the ecology of the endemic Chilean myotis bat (Myotis chiloensis), we carried out morphometric measures and analyzed echolocation calis in a rural site near Pucón (39°15'S 17°W) in the Araucanía Region of southern Chile. During January 2009, we obtained 22 records from captured and 75 records from fiying individuals. The analysis of calis in searching phase showed that the terminal frequency for this species is 43.4 ±1.2 kHz, with a mean duration of 2.1 ± 1.0 ms and an interval between pulses of 77.5 ± 16.9 ms. The calis are FM - QCF, as is characteristic for the family Vespertilionidae. The contribution of new morphometric data from captured and released individuals indicates differences from previous studies. The records and acoustic analysis establishes a baseline for more detailed future ecological investigation of this and other bat species in Chile.