Introduction Our paper presents the aspects regarding the in vitro propagation  and evaluation of different types and concentrations of plant growth regulators used in the inductive multiplcation of fi ve thornless blackberry cultivars: ‘ Loch Ness’, ‚Smoothstem’, ,Evergreen’, ‚Remonthana’, ‚Cester’. Blackberries are popular fruit widely distributed throught nature, except the polar regions, and they grown worldwide. World consumption of blackberies increased in the past few decades, and they are consumed fresh or frozen, and they are found in other comercially procesed food products such as jam, wine, tea, ink, ice-cream, and medicine. Material and methods The micropropagation of Blackberry cultivars was started in 2010 at the Botanical Garden laboratory. Good results were noticed in the process of initiation, multiplication, rooting and aclimatization (Lozinschii, Ciorchină 2013). In the present period new culture mediums, growth regulators and more types of cultivars are being studied. Blackberry micropropagation has been investigated by many researchers (Gajdosova et al, 2006; Meng, 2004; Mihalache, 1996, Zawadska M. and T. Orlikowska 2006 ). Bobrowski, et al. (1996) tested several variants of Murashige & Skoog media with 1 and 2 mg/l BAP. Ružiċ D. and T. Laziċ (2006) carried out experiments of initiation, multiplication and acclimatization using the thornless blackberry cultivar called `Čačanska bestrna`. The highest multiplication rate was ensured by the variant of MS medium with 1 mg/l BAP, 0.1 mg/l IBA and 0.1 mg/l GA3. Results and discussions The basic medium for the morphogenic induction is Murashige - Skoog medium ( MS ) , to which 30 g / l sucrose , 6 g / l agar were added with a 5.6-5.8 pH. For a better and a more effi cient growth and multiplication a MS medium with added hormones was used. The best results obtained in the process of the cultivars multiplication were due to the MS medium created with the BAP growth regulator in different concentrations 0.9 , 0.7 , 0.5 , 0.3 mg / l.  When creating the culture medium with added BAP, the iduction of lateral buds on the ax is considerably increased, which favors a multiple shoot formation ,which then serves as a biological material for the micropropagation and the increase of vegetative mass . When increasing the BAP concentration, an increased number of adventitious shoots with a length of 4-6 cm are obtained and which continue to be subject to the micropropagation process preserving their morphogenic potential . All varietes of plants were micropropagated in the culture medium with added BAP. The most effective results were obtained in such varieties as‘ Loch Ness’, ‚Smoothstem’, ,Evergreen’, ‚Remonthana’, ‚Cester’. To stimulate rootedness process,  a medium with addition of auxins was used ( IBA , NAA ) (Clapa, Fira2011 ) .