BackgroundExtra-urogenital infections due toMycoplasma hominis(M. hominis) are rare, particularly co-infection withPseudomonas aeruginosa(P. aeruginosa). Herein, we report on a patient who was co-infected and successfully treated despite delayed treatment.Case presentationWe reported the case of a 43-year-old man withM. hominisandP. aeruginosaco-infection after a traffic accident. The patient developed a fever and severe infection despite postoperative antimicrobial therapies. The blood culture of wound tissues was positive forP. aeruginosa.Meanwhile, culturing of blood and wound samples showed pinpoint-sized colonies on blood agar plates and fried-egg-type colonies on mycoplasma medium, which were identified asM. hominisby matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) and 16S rRNA sequencing. Based on antibiotic susceptibility and symptoms, ceftazidime–avibactam and moxifloxacin were administered forP. aeruginosainfection. Meanwhile, after the failure of a series of anti-infective agents,M. hominisandP. aeruginosaco-infection was successfully treated with a minocycline-based regimen and polymyxin B.ConclusionThe co-infection withM. hominisandP. aeruginosawas successfully treated with anti-infective agents despite delayed treatment, providing information for the management of double infection.