The application of allelopathy as an alternative strategy that may be included in an integrated weed management package is a current trend in weed science. In this research, the potential of sweetpotato allelopathy was investigated. A greenhouse study showed that sweetpotato cultivars, SG 94-17-17, UPL Sp 3 (Tinipay), UPL Sp 4, UPL Sp 1 (Kinabakab) and UPL Sp 6 (PSB Sp-17 or 88 WS 636) inhibited the growth of purple nutsedge (Cyperus rotundus L.) but the latter was the most suppressive. Laboratory bioassays showed that common purslane (Portulaca oleracea L.) was responsive to the allelopathic, specifically the inhibitory, capacity of sweetpotato while the crops, eggplant (Solanum melongena L.) and corn (Zea mays L.) were partially sensitive, but crowfoot grass [Dactyloctenium aegyptium (L.) Beauv.] and barnyard grass [Echinochloa crusgalli (L.) Beauv.] were not. Folin-Ciocalteu method detected high total phenolic content in the sweetpotato-treated soils that was correlated with the seedling growth of the bioassay species. Based from these results, the allelopathic interactions of sweetpotato with other plants could be applied for weed management.