This paper analyzes corporate bond valuation of a straight bond, and the convertibility feature, when interest rates are stochastic and the firm value is determined by the interaction of a series of stochastic variables. The sensitivity of the corporate debt value to some key parameters is also explored. The methodology applied here is based on a hybrid of simulation and dynamic programming proposed by Raymar and Zwecher in 1997 to value financial American-type options. This methodology proves to be extremely efficient to value American-type options when the sources of uncertainty are numerous