It has been reported that pre-procedure ultrasonography rises the success rate of spinal anesthesia in obese patients. In this article, we performed spinal anesthesia for morbidly obese patient with pre-procedure ultrasonography. And recognizing the lumbar subcutaneous fat gradient in morbidly obese patient was the key to success. A cesarean section was scheduled for a primigravida in her 30 s with BMI 61 kg/m2. The lumbar spine was not palpable. Pre-procedure ultrasonography revealed lumbar subcutaneous tissue getting thicker caudally in the sagittal view. Considering this fact, we adjusted the puncture site and succeeded. Postoperative complications were not observed. The pre-procedure ultrasonography is effective even in morbidly obese patients. It is important to recognize the lumbar subcutaneous fat gradient, the so-called back fat slope, for spinal anesthesia in obese patients.