Nowadays, the recycling of waste materials is one of the important tasks in the world. Not only does it solve the environmental problems but also the economic return provides. The recycled carbon black (CBr) is obtained by recycling of scrap tires using pyrolysis method. In this study, the effect of CBr on consistency limits of clayey soils was investigated. Two different types of clayey soils were used; the first one was high plastic clay (CH) and the other one was low plastic clay (CL). The CBr was mixed with both clays in 0%, 1%, 3%, 5% and 10% percentages at dry state. The liquid and plastic limit tests were performed on the mixtures and also on pure (0%) clayey soils. It is observed that the liquid limit value of CH clay decreases sharply between 0% and 1% CBr contents and then this decreasing trend goes on smoothly. On the other hand, the plastic limit value of CH clay increases with increasing CBr contents, achieves a maximum value at 1% CBr content and then starts to decrease beyond this CBr content. There is no considerable decrease discovered on liquid limit values of CL clay. With a similar manner, the plastic limit value of CL clay decreases with an increase in CBr contents, however, this decreasing trend is not remarkable.