Since the rectangular rod had been used by Eduardo R. Luque in 1979, many authors reported good results by this technique in low back arthrodesis. The advantages of this device are that the technique is relatively easy, the cost is cheaper than the other devices, and no special instruments are needed for application of this device. On the other hand, it has the disadvantage of possible neurologic damage while passing sublaminar wires. The rectangular rod functions fundamentally as a tension band that although it is strong in flexion, it is relatively weak in lateral bending or axial loading on the spine. From June, 1984 to June, 1988, the authors experienced 41 cases of rectangular rod instrumentation with sublaminar wiring in various low back conditions. And 30 cases of spondylolisthesis which could be followed for more than one year were analyzed. And the results obtained were as follows. l. Of 30 patients of spondylolisthesis, 7 cases(23.3%) were male and 23 cases(76.7%) were female. 2. 21 cases(70.0%) were isthmic type and 9 cases(30.0%) degenerative type. 3. 23 cases(76.7%) were in Grade I, 6 cases(20.0%) in Grade II and 1 cases(3.3%) in Grade III, according to Meyerding's classification. 4. At follow up examination, 18 cases(60.0%) were in excellent group, 8 cases(26.6%) in good, 2 cases(6.7%) in fair, according to Gill's criteria. Two cases(6.7%) of pseudoarthrosis were noted and these cases were classified in unsatisfactory group. 5. Rectangular rod with sublaminar wiring was not a good device for reduction of spondylolisthesis