A 2-year-old, spayed male Bengal cat was referred to our clinic due to a mass lesion on the upper lip, as well as lower lip swelling and redness. Furthermore, well-circumscribed, raised, pink lesions were found in the oral cavity. Complete blood counts (CBC) and serum biochemistry profiles revealed no remarkable findings. Bacterial and fungal cultures of the lesion in the oral cavity were negative. Fine needle aspiration of the lesions revealed numerous eosinophils. Based on both clinical examination and cytological evaluation, the cat was diagnosed with feline eosinophilic granuloma. As an initial treatment, oral prednisolone (PDS) with cyclosporine was administered. However, the cyclosporine caused the cat to vomit. The lesion was markedly improved after 2 weeks of PDS-only therapy; this was subsequently tapered for 2 months and discontinued. However, one month later, the lesion had relapsed. The cat was then treated for one month using tacrolimus with PDS, and the clinical signs of eosinophilic granuloma gradually improved. The tacrolimus was gradually tapered for 1 month, and the PDS was gradually tapered for 4 months. There is no standard protocol for the investigation and treatment of feline eosinophilic granuloma. The cat in this report was administered immunosuppressive therapies to treat eosinophilic granuloma. This case report provides evidence the combination of PDS and tacrolimus is effective for reducing relapse in feline eosinophilic granuloma.