Trichoderma longibrachiatum is a fungus belonging to the genus Trichoderma. Trichoderma longibrachiatum is not thought as a pathogenic for healthy individuals. However, it has the ability to produce toxic peptides and extracellular proteases and has been described to cause invasive infections in immunocompromised hosts. Trichoderma longibrachiatum has been reported as the causative microorganism of lung infections, skin infections, sinus infections, otitis, stomatitis endocarditis, pericarditis, gastrointestinal infections, mediastinitis and peritonitis. We report the first case of pneumonia with parapneumonic effusion in an old woman with diabetes mellitus due to Trichoderma longibrachiatum.