SUMMARYNet synthesis of protein and RNA in germinating macroconidia of Fusarium solani began at the time of appearance of germ tubes, RNA being formed first; net DNA synthesis began much later. Studies on precursor incorporation indicated that the ungerminated spore, at the time of its removal from the parent mycelium, had a low but real capacity to synthesize both RNA and protein. Leucine incorporation rose very rapidly to a maximum at about 40 min. after harvest; even in the time required for conventional washing and filtration, incorporation capacity increased threefold. Ultracentrifuge profiles showed polysome peaks after I 5 min. incubation ; evidence from ribonuclease treatment was consistent with the existence of polysomes in the spore at the time of removal from the mycelium. Neither protein nor RNA synthesis required a complete medium, but DNA was synthesized only in a medium that supported germination.