A great deal of work has been devoted to determine the effect of tissue damage produced by alpha particles emitted from radon and its progeny. (214)Pb and (214)Bi deposited in the human lungs emit beta particles followed by the gamma quanta, which cause smaller damage of tissue in comparison with alpha particles. Because of that, this type of irradiation has not been studied in detail. In this paper, doses from beta and gamma rays emitted by radon progeny (214)Pb and (214)Bi in the lungs have been calculated in all main organs and the remainder tissues of the human body. Human Oak Ridge National Laboratory phantom of adult male and female was used, where simulation was performed using MCNP-4B simulation code. The sources of beta and gamma radiations, namely, the radon progeny were located in lungs. Furthermore, dose conversion coefficients have been calculated.