The aim of the study was to identify the causes underlying overgrowth of incisors in chinchillas through an analysis of selected plasma electrolyte concentrations, with particular consideration of minerals involved in the formation of osseous tissue, i.e. Ca,Mg, and P. The analysis involved 40 female standard chinchillasmanaged in a commercial farmsystem, aged 2 to 4 years, divided into two groups of 20 individuals each: D . chinchillas with incisor overgrowth and C . controls with normal dentition. Concentrations of Ca, Mg, and P were measured in blood plasma. The analysis was carried out using ICP OES (inductively coupled plasma optical emission spectrometry) by means of the Optima 2000 DV instrument (Perkin Elmer). The resulting data were analysed statistically using one-way ANOVA with Duncan.s range test. The results show that abnormal metabolism of dental tissue minerals, especially Ca and P, cannot be excluded as the cause of tooth overgrowth in chinchilla.