The deformation and fracture behavior of SM-200, a nickel-base alloy, was studied at room temperature under tension and flexural loading. Electron fractographic techniques were extensively used to determine which phases and fracture mechanisms contributed to the fracture process. In addition, an investigation of the phase constitution of SM-200 using electrolytic phase extraction was conducted in order to relate mechanical behavior to alloy microstructure. A solution heat treatment was employed in an attempt to produce a microstructure exhibiting properties superior to those shown by as-cast material. Failure was found to occur along subgrain boundaries containing titanium carbide particles and massive γ′ clusters in as-cast materials, while TiC and M₂₃C₆ particles were considered responsible for subgrain boundary fracture in solution heat-treated specimens.