A 20 year old female, 14 days post partum, presented to the Emergency Department in severe respiratory distress. Imaging of her chest revealed a left tension hydropneumothorax with significant mediastinal displacement. A chest drain was inserted and over 4L of cloudy-brown malodourous fluid was drained. Gardnerella Vaginalis was isolated on culture of the fluid. The pyohydropneumothorax and associated sepsis, was refractory to management with a chest drain and antimicrobial therapy. She required a video-assisted thoracoscopic surgery and decortication of her unexpanded lung. She ultimately made a full recovery. Gardnerella vaginalis is considered a dysbiosis of the genitourinary tract, rather than an overtly virulent pathogen. Although extremely rare, there are occasional reports of Gardnerella vaginalis causing infection, even at sites distant from the genitourinary tract. To our knowledge, this is the first documented case of Gardnerella vaginalis causing respiratory sepsis and a pyohydropneumothorax in a healthy, immunocompetent female during the post-partum period. Although it is a unique case, nevertheless, it highlights the need for physicians to be congnisant of G. vaginalis as a potential pathogen when treating post-partum sepsis and indeed, even as a potential pathogen when treating pulmonary infections in obstetric patients. This will lend to prompt initiation of appropriate antimicrobial treatment.