In this paper, author's results of several years of research work on the mechanical properties of directionally solidified (In-Situ) composites are reviewed. Alloy systems investigated were the fibrous AI-Ni, Fe-MnS and the cobalt base superalloy Co-Cr-C and the lamellar AI-Cu and Co-W. The mechanical behavior of the above systems were studied under both static and dynamic loadings. Static loading involved tension, compression and 3-point bending and the dynamic loading involved rotating bending fatigue, fatigue crack propagation and strain controlled fatigue. It was found that the tensile fracture stress and toughness and the ultimate compressive stress were generally enhanced by increasing growth rate and/or temperature gradient. However, at very high growth rates, the properties were found to decrease due to misalignment of the structure. Models were suggested to describe the static behavior of the composites investigated. Good agreement was found between the model predictions and the experimented results which indicate that the static properties are structural sensitive. On the contrary, the fatigue life of the AI-A13 Ni was insensitive to structural changes caused by varying the growth rate. The fatigue crack propagation response of the Co-Cr-C composites was found to follow the Paris Erdogan relation. Examination of the fracture surface confirmed a brittle mode of fracture with fiber cleavage and matrix shearing to link up fiber breaks.