Single crystalline Co₃Ti base quarternary compounds, (Co, Ni)₃(Ti, Al), are prepared and the effects of temperature, strain rate and orientation on the plastic behavior are investigated. Then the results are compared to other L1₂ intermetallic compounds being represented by Ni₃Al. The differences found by the comparison are as follows. (1) Regardless of the crystallographic orientation with respect to the stress axis, there is a strong negative temperature dependence of strength at low temperature regime. (2) Plastic deformation is accompanied by serration on the stress strain curve and by metallic acoustic emission in the single crystals with near-[111] orientation and at temperature regime between 77 to 973 K where the anomalous positive temperature dependence of strength is observed. (3) For the same orientations, the temperature regime where cube slip governs the plastic deformation is narrow. (4) Octahedral viscous flow at the high temperature regime is not associated with well-defined yield drop. It is to be noted that the plastic behavior of Co₃Ti base single crystals should also be discussed seperately in the above four regimes as has been done in other single crystalline L1₂ compounds.