Class III beta-tubulin has been discovered as a marker of early phases of neuronal differentiation in developmental conditions, as well as in different tumours of neuronal origin. More recently, the expression of class III beta-tubulin molecule has been described as a marker of different types of malignant epithelial tumours. This study attempts to compare the immunostaining features of two different mouse monoclonal antibodies TU-20 and TuJ-1, both detecting class III beta-tubulin, in a group of twenty bioptically evaluated carcinomas of various sites. The proposal that class III beta-tubulin expression can correlate with the degree of tumour differentiation and thus could be potentially used as predictive marker of prognosis has been previously done; one of aims of our study was to confirm this hypothesis. Our results showed that both TuJ- 1 and TU-20 antibodies displayed similar immunostaining profile and pattern within individual tumours. Surprisingly, we discovered that only 50% of tumours included in our group showed expression of class III beta-tubulin, however, positive immunoreaction did not correspond with the degree of differentiation of individual tumours. In our group of carcinomas, the class III beta-tubulin positivity was not related to the tumour site, histologic type of tumour or its grade.