Biofuels Security Tax Act of 2006

Biofuels Security Tax Act of 2006 - Amends the Internal Revenue Code to allow until 2017 a tax credit for flexible fuel vehicles. Defines "flexible fuel vehicle" as a motor vehicle which can operate on both gasoline and a blend of 85% ethanol and which is certified as having the same or better fuel economy rating when operating on 85% ethanol or on gasoline only.

Extends until 2017 the tax credit for alternative fuel vehicle refueling property (service stations for dispensing alternative motor fuels to retail consumers). Increases the rate of such credit to 50% for all taxpayers and to 75% for taxpayers who place in service not more than five such refueling properties. Denies such credit to major oil companies (companies having at least 4,500 retail service stations).