The use of tilting-pad journal bearing (TPJB) has increased in the recent past due to their stability effects on the rotor bearing system. The first part of this paper presents a review of the state of the art work on rotor response when supported on TPJB. Only few published work presented results relating to the strongly nonlinear behavior, especially chaos, resulting from the use of these types of bearings. In the second part of this paper, three loading mechanisms capable of producing instabilities in terms of sub-harmonic and chaotic motions are suggested. The first one is that of a centrally loaded pad with small rotor unbalance excitations. The second one is when the load is applied between two pads. And, the third represents a concentric rotor (zero static load) acted upon by centering sprigs and unbalance excitation. After a quite extensive numerical experimentation, the resulting response shows, for certain parameters, sub-harmonic, quasi-periodic and chaotic motions.