The objective of this paper is to present our experience in the commissioning and quality assurance (QA) of PrecisePLAN treatment planning system for intensity modulated radiotherapy (IMRT) using multileaf collimator (MLC), step and shoot technique. The data were obtained during the installation, acceptance test procedure, and commissioning of the unit. The dosimetric data were taken using CC13 pin-point ion chamber (Scanditronix Wellhofer). The beam profiles for various field sizes in the x, y, and diagonal directions were measured. The basic dosimetry parameters such as percentage depth dose (PDD), off-axisratio (OAR), output factor, and scatter factors needed for patient treatment were evaluated. Point dose measurement and fluence maps did the treatment dose verification. [Turk J Cancer 2007;37(1):22-26]