In this study, it was aimed to reveal prospective elementary mathematics teachers’ abilities of usinggeometric proofs in triangle teaching. The data of this study which was based on the techniques of qualitativeresearch was obtained from students attending third class of elementary mathematics teacher education programat a public university in the north of Turkey, in 2013-2014 academic year. As data colletion tool, five openended questions which were prepared by the researchers taking the opinions of experts were used and theobtained data was analyzed through content analysis. The results show that proving abilities of prospectiveteachers are low. Three volunteer prospective teachers were made a semi-structured interviews with the intent ofexamining their proofs in detail. The obtained interview data have exposed that prospectice teachers usuallyattempt to produce geometric proofs using elementary, concrete and practical solution ways in terms of their ownperpectives.