Aim: To highlight the diagnosis and management of a delayed presentation of unilateral choanal atresia in adulthood. Background: Otorhinolaryngology hosts a spectrum of congenital anomalies, but not all are easy to diagnose. Unilateral choanal atresia is very rare and usually occurs without syndromic associations. It generally presents in late childhood as unilateral nasal obstruction, sometimes gets missed, and masquerades as other commoner causes in adulthood. It needs apt management by surgical reconstruction. Case description: A 22-year-old male presented with unilateral nasal obstruction and foul-smelling nasal discharge since childhood with no relief after using nasal sprays and drops. Clinically and radiologically, it was found to be a grossly deviated nasal septum and was taken up for surgery when we unearthed the true diagnosis as choanal atresia. It was then corrected by microdebrider-assisted neochoana creation, and a novel stent was made by refashioning the nasopharyngeal airway. Postoperatively, complete patency was obtained with an excellent outcome and symptomatic relief. Conclusion: The diagnosis of choanal atresia in adults is seldom easy; they may present with thick nasal discharge and gross posterior deviations, making even endoscopic evaluation difficult without first having to do septoplasty. Also, membranous and mixed atresias are not picked up by the scans due to a lack of radio-opacity, as we observed. Surgical correction is imperative for relief. Clinical significance: Diagnosing unilateral choanal atresia, that too in adults, requires immense clinical suspicion as a wide range of differentials may exist for the same presenting features. Performing a microdebrider-assisted removal of atresia without needing a posterior septectomy and using a simple, easily available nasopharyngeal airway by refashioning it as a stent gave a fine outcome. Restenosis was encountered in 70% of cases, as reported in the literature, but we found complete patency even after 6 months. Thus, choanal atresia must be kept in mind by the rhinologist in his daily practice while evaluating even adults with nasal obstruction.