A weather resistant, rodenticidal bait comprises sweet corn flour, an effective amount of a rodenticide, and water. Additional preferred ingredients include a glutinous flour, flavoring and salt. Preferred rodenticides include diphacinone, brodifacoum, warfarin, bromadialone, bromethalin and their functional equivalents. A preferred method of manufacturing the weather resistant rodenticidal bait of the present invention utilizes cold extrusion techniques. The most preferred method of manufacturing includes the steps of mixing a sweet corn flour, an effective amount of a rodenticide, and water to produce a rodenticidal mixture. In the preferred method, a glutinous flour is also mixed with the sweet corn flour, with wheat flour the most preferred glutinous flour. The rodenticidal mixture is forced through an extrusion chamber and out a nozzle opening, to produce extruded chunks. The extruded chunks are preferably dried to obtain weather resistant, sweet corn-based rodenticidal bait having a sweet corn content of at least 65% by weight of the weather resistant bait and a moisture content of not more than 10% by weight of the weather resistant bait.