The aims of the study were to investigate if human adult mesenchymal stem cells (MSCs) can transdifferentiate into muscular cells with specific genetic features, and to analyse if there is a correspondence between the type of stimulation and the amplitude of gene expression. Cells were extracted after previous filtration and density fractioning of the marrow aspirate. They were seeded and cultured in Iscove’s modification of Dulbecco’s medium (IMDN) with 20% fetal calf serum (FCS), penicillin and streptomycin, at 37°C in a 5% CO₂ environment. Cultures reaching 80% confluence were reseeded in 24-well plaques and split in two different groups according to the stimulation pattern. Continuous pattern implying maintenance of 5-azacitydine (1,2} in culture for the entire time length and discontinuous pattern implying removal of 5-azacitydine after 24 h followed by another addition after 24 h (6 samples in triplicate for each type of experiment). Within a 5 week interval of stimulation cultures from both groups underwent morphological changes. Cells begun to entangle developing colonies in which they started to multiply forming layers which gave a tissue-like appearance of the colonies. Round shaped cells, with different morphological features, rose within the colonies by the third week of culture. A decrease in cell density was noticed particularly in the continuously stimulated cultures. Total RNA was extracted followed by reverse transcription, the resulting cDNA was subjected to quantitative PCR analysis for genes encoding myogenin and myogenic factor 5 (MYF5), both specific for muscular cells (3). As positive controls we used an acute myelogenous leukemia (AML) sample, which highly expresses the two markers. Results showed a more enhanced expression in the continuously stimulated cultures with a peak at 30th cycle versus 35th cycle for both markers, suggesting that the stimulated cells produced a higher amount of specific RNA. The efficiency of RNA extraction and reverse transcription was assessed by glyceraldehyde-3-phosphate dehydrogenase (GAPDH) analysis. We conclude that 5-azacitydine stimulation induces synthesis of muscular specific RNA in MSCs (3,4). Continuous culture in the presence of 5-azacytidine induces higher gene expression, while discontinuous stimulation allows better cell survival.