Pleural trichomonosis is clinically rare, and very few cases of trichomonal empyema have been reported so far. A rare case of an 81-year-old woman with pyopeumothorax presenting with recurrent fever and macroscopic pyuria was present. Microscopic examination of the pleural effusion showed mobile flagellated protozoa which molecular methods identified as Tetratrichomonas. In addition, Streptococcus anginosus was discovered in pleural fluid cultures. Treatment with imipenem/cilastatin and metronidazole successfully eliminated the pathogens and led to relief of clinical symptoms. In the context of a review of the relevant literature, the clinical application of molecular methods in the diagnosis of pleural trichomonosis is underlined.