Prepare canner, jars, and lids. In a stainless steel saucepan, combine corn syrup, sugar, and water. Heat over medium head stirring till dissolved.
Increase heat and bring to a boil for one minute. Reduce heat and stir in pecans and vanilla. Boil gently, stirring constantly for 5 minutes.
Ladle hot syrup into hot jars, leaving 1/4" headspace. Wipe rim, add lid and rings and process in water bath for 10 minutes at a full boil. Remove jars and cool on dishtowel overnight.