Effect of ionizing radiation on survival of bacteria, fungi and red gram seed (Cajanus cajan L.) germination was assessed in laterite soil in the laboratory. The mercury vapor lamp (l = 400 nmâ€700 nm), sodium vapor lamp (l =589.3 nm ) and ultra violet (l = 400 nm †10 nm) radiations were exposed to the laterite soils for 20, 40, 60 and 80 min and their effect on survival of bacterial, fungal colonies and seed germination were enumerated. Sodium vapor was found to be very effective in inhibiting the bacterial and fungal populations. Ultra violet radiation was efficient in reducing the survival of the microbial densities than mercury vapor lamp. In the exposed soil, the germination of seeds in terms of percentage, the stem length (SL) and root length (RL) of seeds were calculated at 7th day of incubation. The laterite soil was shown significant stimulation in the germination of seed at 40 min exposure with ultra violet radiation. Results obtained in the present study indicate that the energy captivated by molecules was prominent at lower radiation and shorter exposure time enhanced the proliferation of bacterial cells and red gram seed germination.