A three-dimensional (3-D) multi-species magnetohydrodynamic model was used to study the interaction of Titan's ionosphere and Saturn's magnetosphere. The three generic species which were considered are light (e.g., H+, H2+, and H3+), medium (e.g., N+ and CH5+), and heavy (e.g., N2+ and HCNH+) ion species. The effects of exospheric mass loading, major chemical reactions, and ion-neutral collisions were considered. The upstream parameters were selected to be the nominal values for the case when Titan is in the magnetosphere of Saturn. The simulation results are compared with Voyager measurements as well as related model calculations. The 3-D three-species model results reproduce reasonably well the global features such as magnetic barrier, magnetotail, and the distributions of the major ionospheric species. The outward escape flux of the major ionospheric species (i.e., the heavy ion species) from the tail is calculated to be approximately 6.5¿1024 s-1. ¿ 2001 American Geophysical Union