Patrik Karlsson FX BASKET OPTIONS - Approximation and Smile Prices - Abstract Pricing a Basket option for Foreign Exchange (FX) both with Monte Carlo (MC) techniques and built on different approximation techniques matching the moments of the Basket option. The thesis is built on the assumption that each underlying FX spot can be represented by a geometric Brownian motion (GBM) and thus have log normally distributed FX returns. The values derived from MC and approximation are thereafter priced in a such a way that the FX smile effect is taken into account and thus creating consistent prices. The smile effect is incorporated in MC by assuming that the risk neutral probability and the Local Volatility can be derived from market data, according to Dupire (1994). The approximations are corrected by creating a replicated portfolio in such a way that this replicated portfolio captures the FX smile effect.