Background: Bacteria of the genus Providencia are emerging pathogens associated with a wide range of infections, particularly in healthcare settings. In veterinary medicine, infections caused by these organisms are uncommon, and, to date, there have been no reports of carbapenem-resistant Providencia spp. causing infection in companion animals. Methods and Results: This study describes a comprehensive investigation of bacterial endocarditis caused by carbapenem-resistant Providencia rettgeri in a cat, including clinical, imaging, pathological, microbiological, and genomic findings. A 1.5-year-old mixed-breed female cat was admitted to a referral veterinary hospital with an extensive pelvic limb wound and a recent history of laparotomy. During hospitalization, a heart murmur was detected, and echocardiographic examination revealed vegetation-like lesion on the mitral valve. Despite intensive treatment, the patient’s clinical condition progressively deteriorated over a 15-day period, ultimately leading to euthanasia. Necropsy confirmed bacterial endocarditis with evidence of systemic septic embolization. P. rettgeri was isolated from blood collected from both heart ventricles and from an endocardial swab and its identity was confirmed by MALDI-ToF mass spectrometry. Antimicrobial susceptibility testing demonstrated resistance to meropenem. Whole-genome sequencing confirmed the species identification and revealed a Col3M plasmid carrying multiple antimicrobial resistance genes, including the carbapenemase gene bla_NDM-1. Discussion: To the best of our knowledge, this is the first report of carbapenem-resistant Providencia spp. causing infection in a companion animal. This case highlights the emergence of Providencia spp. as potential veterinary pathogens capable of causing severe, invasive and fatal infections.