Protective barriers against primary and secondary radiation are necessary in x- and gamma -ray rooms. As well as absorbing radiations, these barriers inevitably scatter radiation back into the room. Hence it is important to determine this factors which affect quantity and natare of scattered radiation in order to find means to minimize the effects. Investigations on qnantity and quality of radiation scattered from lead and concrete walls of density 2.4 g/cm/ sup 3/ are reported. The effects of covering concrete with lead sheets of different thicknesses was also studied for the energy range 0.085 to 2.76 Mev. (auth)