Volumetric modulated arc therapy (VMAT) provides the possibility to deliver comparable dose distributions to the established IMRT techniques. In the case of VMAT, the treatment efficiency can be increased due to the available degrees of freedom (like gantry speed, collimator angle, dose rate and leaf position). Before implementing VMAT into our clinical routine, we compared data consisting of 9 patients with prostate cancer between calculated VMAT plans, film and ionization dosimetry. In addition the first patients also received rectal in-vivo measurements. The VMAT plans were generated with the treatment planning system (TPS) ERGO++ (ELEKTA, Crawley/UK) for the 9 prostate cancer patients. On each patient CT dataset, two plans (1 rotation vs. 1.5rotations) were calculated. The verification was made by the use of films- (edr2, KODAK) and ionization dosimetry (0.125cm3/ PTW Freiburg) in a homogeneous phantom. The complete Dicom Export from ERGGO++ to the record and verify system Mosaiq (Impac, Elekta) and to the Elekta Synergy machine was verified. The resulting dose distribution of the irradiated films were analyzed by profiles and γ-index analysis. An appropriate ion chamber of type 23323 (PTW Freiburg, Germany) for the in-vivo measurements was used. The plans were transferred from ERGO++ to the R&V system and further to the linac without any deviations. The mean monitor units for prescription dose of 2Gy were 312±20MU. The deviations noticed with the ionization dosimetry for the 1.5 rotations were less than 2% (0,69±0.43%). The plans with just one rotation showed deviations less than 3% (2.59±0.8%), except 2 plans with measurements close to the high gradient region, had a deviation between 3% and 4%. The γ-index analysis of the film dosimetry showed no plan with a deviation higher than 3%/3mm in high dose region. The analysis of the high- and low dose region in the γ-index showed that 40.9±8.7% met the requirements for the γ-index criteria of 1%/1mm, 84.8±8% for 3%/3mm and 97.2±2.7% for 5%/5mm. The in-vivo measurements showed a good agreement between calculated and treated dose (1.76±0.47%). VMAT plans can be planned and treated reproducible in high quality after the commissioning the complete chain from TPS over R&V system to the linac. The results of the individual plan verification meet the general published requirements. The first in-vivo measurements confirm the precision of the delivered dose.