An 81-year-old male, anticoagulated for atrial fibrillation, presented with a cat bite on his left hand. Despite initial prophylactic antibiotic treatment, the patient developed a flexor sheath infection of the hand. Surgical debridement was necessary and confirmed Pasteurella multocida infection. He was treated with intravenous amoxicillin/clavulanic acid, followed by oral therapy for two weeks. The patient recovered fully, with normal hand function at 12 months. This case underscores the importance of early intervention in cat bites, as they carry a high risk of infection.