The aim of this study was to determine the phenolic composition and antiproliferative activity of five water extracts of plants which belong to Lamiaceae family. The aerial parts extracts of the plants, obtained from Teucrium montanum, Calamintha nepetoides, Satureja subspicata, Salvia sclarea and Melissa officinalis, were tested on human prostate cancer (T24) and human breast cancer (MDA-MB-231) cell lines by using the MTT assay. The phenolic content of the plants were determined by high performance liquid chromatography (HPLC). Among the tested extracts, the extract of Teucrium montanum showed the best antiproliferative activity against T24 and MDA-MBA-231 cell lines. Furthermore, the extract of Satureja subspicata and Melissa officinalis showed significant antiproliferative activity against T24 cell line, too. Generally, all extracts showed better antiproliferative activity against T24 cell line in comparison to MDA-MBA-231 cell line. The HPLC data of the plant extracts showed the presence of the following phenolic compounds: protocatechuic acid, caffeic acid, p-coumaric acid, cinnamic acid and predominatly rosmaric acid. The findings of this study indicate that there is some justification for the use of the tested plants as traditional anticancer medicinal herbs.