Purpose: Bilateral inferior petrosal sinus sampling (IPSS) is a direct method of distinguishing between pituitary and ectopic ACTH secretion. We present unilateral femoral route technique avoiding bilateral femoral venous puncture using two 4F catheters into both sides of IPSS in these obese patients.Materials And Methods: Unilateral femoral puncture using 9F guiding catheter allowed two 4F catheters which can be introduced in each side of inferior petrosal sinus. To reduce bleeding in the gap between 2 catheters at the diaphragm of the 9F femoral sheath, we introduced a short guidewire provided along with femoral sheath. After removing the 9F sheath after procedure, we applied manual compression as usual. We evaluated any technical difficulty and other complications including the presence of hematoma at the puncture site 1 day and 30 days later.Results: Bilateral IPSS by using two 4F catheters in both inferior petrosal sinuses was possible via unilateral femoral route via 9F sheath. There was no technical difficulty introducing 4F catheters into each IPS of both sides. After removing 9F femoral sheath, there was no other complication and no hematoma at the puncture site at 1 day and 30 days later.Conclusion: Unilateral femoral venous approach with a 9-French sheath can be used in IPSS. This technique allowed to pass two 4F catheters for IPSS at both sides and could avoid unnecessary bilateral femoral puncture in these obese patients without any hematoma formation after the procedure.