The present invention relates to Chimeric Antigen Receptors (CAR) that are recombinant chimeric proteins able to redirect immune cell specificity and reactivity toward selected membrane antigens, and more particularly in which extracellular ligand binding is a scFV derived from a ROR1 monoclonal antibody, conferring specific immunity against ROR1 positive cells. The engineered immune cells endowed with such CARs are particularly suited for treating lymphomas and leukemia, and for solid tumors such as breast, colon, lung, and kidney tumors.