This work is based on the activated carbon production from coal by physical activation in a fluidized bed reactor by an autothermal process (without an external energy source). Coal from Amaga region (Antioquia - Colombia ) was activated in two fluidized reactors, 10 and 22 cm of diameter. The specific surface area and pore volumes values were determined by gas adsorption of N2 and CO2. Experimental results revealed that the BET and DR surface areas and Iodine Number values oscillated near to 460 m2/g (SBET), 490 m2/g (SDR) y 460 mg I2/g carbon.