The authors describe a case of impossible intubation by classical means in an obese 37-yr old woman, affected with encephalopathy, hydrocephalus and severe psychomotor retardation. After failure of intubation by classical methods using a flexible introducer, the patient was intubated by Waters retrograde technique using an epidural catheter passed through the thyrocricoid membrane and recovered in the mouth. Following this guide the endotracheal tube passed the glottis fairly easily with the help of a flexible "mouse tail-ended" introducer (C-Mettro, Cook, 19.0.80) inserted into the same tube to facilitate alignment of distal tube and trachea. The authors conclude that the combination of epidural catheter and flexible introducer may facilitate the retrograde technique performance; they consider this technique to be an interesting alternative when endotracheal intubation is difficult or impossible by usual methods.