Systemic candidiasis with renal involvement is a rare but well-recognized complication during neonatal intensive care treatment. In addition to intravenous administration of amphotericin B, decompression of the renal pelvis and irrigation of the involved kidney with the same drug through a nephrostomy tube will provide a high concentration of antifungal agent with a flushing effect. This procedure is not always possible due to the small size of the neonatal kidneys. We have conceived a new percutaneous trocar nephrostomy which allows its application directly in an incubator without using X-rays during a single procedure. In 3 cases a bilateral percutaneous nephrostomy was performed directly in the incubator using a one-step ultrasonically guided maneuver under local anesthesia. The funguria was successfully eradicated in all cases. The availability of a nephrostomy trocar of small dimensions leads us to an improved renal approach in newborns.