Bartonellosis is a group of emerging and re-emerging bacteria of Bartonella genus with worldwide distribution. Bartonella species cause diseases such as Carrión's disease, trench fever, cat scratch disease, bacillary angiomatosis, peliosis hepatis, chronic bacteremia, endocarditis, chronic lymphadenopathy, and neurological disorders. Fleas, lice, sand-flies, bed bugs, ticks, mites, and even spiders transmit infection to man, domestic and wild animals. Infection is establishing intracellular replication niches and subverts diverse pathways of host's immune system. Bartonellosis can subclinical bacteremia to broad spectrum of clinical symptoms in man ranged from a mild flu-like intermittent fever to more severe manifestations such as, arthralgia, arthritis, endocarditis, hepatitis, myocarditis, neuroretinitis, uveitis, vasoproliferative tumors and even death.Effective antibiotics include rifampin, ciprofloxacin, gentamicin, and trimethoprim/sulfamethoxazole. But, B. henselae is generally resistant to penicillin, amoxicillin, and nafcillin. Doxycycline and rifampin in combination are recommended to treat neuroretinitis. Treatment must be adapted to each clinical situation, species, and acute or chronic disease, but in a timely manner.