Abstract: Laboratory experiment was conducted in the Microbiology Laboratory of School of Science and Science Technology, Abubakar Tafawa Balewa University, Bauchi, Nigeria in May, 2012 to determine the antifungal effect of different concentrations of neem and moringa seed extracts on wet rot disease of sweet potato. Moringa and neem seed extracts each with four varying concentrations (30,60,90,and 120g/L) were evaluated along with carbendazim and untreated sweet potato serving as a control constittuted the treatments. The treatment were laid out in Completely Randomized Design (CRD) with three replications. The result showed that neem seed extact was significantly (P < 0.01) better than th moringa seed extract in controlling the disease. Treatment of the sweet potato with varying concentrations of neem and moringa seed extracts significantly (P < 0.01) inhibited radial mycilial growth of R. stolonifer and also reduce the weight loss of sweet potatoes caused by R. stolonifer compared with the control, except the application of 25g/1 of moringa seed extract. Preventive method of control significantly reduce the disease than the curative method. The effectiveness of the two plants seed extracts compared favourably with carbendzim. The study revealed that there exist a potential in natural plant products for the control of crop diseases, and if fully exploited, they can replace chemical pesticide in the control of crop diseses. It is therefore recommended that farmers should used 90g/1 or120g/1 as postharvest treatment for sweet potatoes before storage as control measure for R. stolonifer.