Arvand is a robot specially designed and constructed for playing soccer according to RoboCup rules and regulations for the medium size robots. This robot consists of three main parts: mechanics (motion and kicker); hardware (image acquisition; processing and control unit) and software (image processing; motion control and decision making). The motion mechanism is based on a drive unit; a steer unit and a castor wheel. Robot machine vision system uses a CCD camera and a frame grabber. Two microcontroller based boards are specially designed for carrying out the software system decisions and transferring them to the robot mechanics. The software system can perform real time image processing and object recognition. It implements algorithms for playing soccer. These algorithms are written in a high level language "ArvandLan" specially designed for mobilizing these robots. By changing the algorithms our robots can play as goal keeper; attacker or defender. We have constructed 5 such robots and successfully tested them in a soccer field defined according to RoboCup regulations.