Ciprofloxacin is the most commonly used fluoroquinolone. Ciprofloxacin is prescribed for 1 in 44 Americans. Ciprofloxacin is a broad-spectrum bactericidal antibiotic, effective against both gram-positive and gram-negative bacteria, being especially active against the Enterobacteriacae, including many microorganisms resistant to penicillins, cephalosporins and aminoglycosides, and also is effective against Haemophilus influenzae, penicillinase-producing Neisseria gonorrhea, Campylobacter and Pseudomonas aeruginosa. Streptococci and pneumococci are weakly inhibited and there is a high incidence of staphylococcal resistance to ciprofloxacin. In neonates, the dose of ciprofloxacin is 10 mg/kg intravenously over 30-60 min infusion, and 20 mg/kg is used to treat Pseudomonas aeruginosa infection. Ciprofloxacin treatment is effective in life-threatening multi-drug resistant Pseudomonas aeruginosa. Ciprofloxacin may be administered by mouth and has a bioavailability of 70% and is mainly recovered unchanged in the urine. Ciprofloxacin is safe and well tolerated in infants. In neonates, the half-life of ciprofloxacin is 3-4 hours. For meningococcal prophylaxis, give a single dose of 30 mg/kg (up to a maximum of 125 mg) orally. Ciprofloxacin is active against Citrobacter kosery that produces brain abscesses. The mortality rate for meningitis due to Citrobacter kosery is approximately 30%. Third-generation cephalosporins and aminoglycosides failed to prevent the high rates of morbidity and mortality caused by Citrobacter infections. Ciprofloxacin is the antibiotic treatment option for systemic infection or meningitis caused by Citrobacter kosery. Ciprofloxacin has been used to treat neonatal pneumonia, meningitis, and septicemia and was effective in all cases. The aim of this study is to review the clinical pharmacology of ciprofloxacin in neonates.