This paper discusses the case report on Mycoplasma infection in cat and its timely diagnosis by blood smear examination and haematology. It also discusses the treatment and response of the cat for the disease. Haemobartonellosis in cats is caused by Mycoplasma haemofelis, formerly known as Haemobartonella felis. An eight months old Persian cat was received in the Small Animal Clinics, Out Patient Ward, Medicine department, Madras Veterinary College with the history to suspect for feline Mycoplasmosis. Peripheral blood smear and whole blood sample was collected and subjected to blood smear examination and whole blood for routine haematological study. It revealed codocytosis, anisocytosis and hypochromasia. Few ghost cells also were seen. Nearly 80–85% of the RBCs revealed darkly stained small organism at the rim or periphery of the cells.