Valuing financial assets when the world is not as normal as assumed by many financial models requires a method flexible enough to function with different distributions which, at the same time, can incorporate discontinuities such as those that arise from jump processes. The Monte Carlo method fulfills all these requirements, in adition to being accurate and efficient, which makes this numerical method the most suitable one in those cases that do not conform to normality. This paper applies Monte Carlo to the valuation of financial assets, specifically financial options, when the underlying asset follows stochastic volatility or jump-diffusion processes.