Swyer-James syndrome (SJS) or Swyer-James-MacLeod syndrome is a rare disorder characterized by roentgenographical hyperlucency of one lung, lobe, or part of a lobe. As originally described, it shows a unilateral small lung with hyperlucency and air trapping on radiographs. It is postinfectious obliterative bronchiolitis due to childhood respiratory infection. In SJS, the involved lung or portion of the lung does not grow normally. The characteristic radiologic appearance is that of pulmonary hyperlucency on chest X-ray/CT caused by over-distention of the alveoli in conjunction with diminished arterial flow detected on Tc-99 m MAA pulmonary perfusion scan. Radionuclide pulmonary ventilation studies are considered difficult to perform in very young children as patient co-operation is crucial to achieve adequate tracer entry into the lungs. We present here the case of a female child aged 2 years, who presented with chronic productive cough and fever off and on for 1.5 years. She had classical features on imaging and markedly diminished ventilation on Tc-99 m DTPA aerosol study. Our case highlights the typical findings on ventilationperfusion scan (V/Q scan) and suggests that it is possible to conduct a satisfactory ventilation study with Tc-99 m DTPA aerosol even in very young children.