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Among types of renewable energy resources, wind energy is considered the fastest developing and most competitive. Counter-rotating turbines (CD-RWT) were adopted in order to enhance the efficiency of the system and overcome the difficulty of large-scale wind turbine installation and maintenance. This paper is devoted for design and predicting the actual performance of a counter-rotating multi-rotor horizontal axis wind turbine. The wind turbine rotor is initially designed by Q blade software based on the modified blade element momentum theory and is used to assess and analyze the design and performance as well. The wind turbine blades have been manufactured for both rotors with a radius of front rotor and rear rotor of 0.61 m and 1.17 m respectively and fixed to a single 600W PMSG generator. Results showed that the power coefficient at low wind speed is very satisfactory and put within the acceptable range. The most important improvement was fixing the aerodynamic deficit at the root of back-rotor blades and therefore improving the self-starting characteristics. The constructed wind turbine start-up has been rated from 2 m/s to 4.5 m/s as the maximum speed, which is consistent with the wind characteristics of Iraq. The coefficient of performance (cp) was found 0.46,0.41 for single wind rotors and 0.50 for twin-rotors experimentally. While cp was found-for single rotors wind turbine 0.49,0.43 and for twin rotor 0.54 theoretically. A comparison between theoretical and experimental results was conducted and its revealed good closeness to the overall outcome. [ABSTRACT FROM AUTHOR]