Neonates frequently receive amikacin as empiric therapy for severe infections caused by suspected Gram-negative bacteria. Optimum dosing of amikacin is required because of the inter-individual variability in the pharmacokinetics in the neonatal population.This study was conducted to compare the efficacy and safety (nephrotoxicity) of once daily versus twice daily dosing of amikacin in suspected or proven sepsis in neonates in relation to the pharmacokinetics of the drug as well as amikacin pharmacokinetic parameters determination under these two dosing schedules in the septic neonates of the Egyptian population.The study included 100 neonates of gestational age ≥ 36 weeks and body weight ≥2500g with suspected or proven sepsis divided into two groups: (Group I) included 50 neonates who received amikacin at a dose of 15 mg/kg once per day while ( Group II) included the other 50 neonates who received amikacin at a dose of 7.5 mg/kg twice per day.Blood samples for amikacin determination have been taken during treatment, after the completion of 1-hour i.v. infusion (peaks) and just before the next dose (trough).Nephrotoxicity was assessed by serum urea and creatinine at the onset and after 3-5 days of amikacin therapy and urine volume throughout the duration of amikacin therapy In the current study we found that the measured amikacin peak concentration in the once daily group (Group:1) (mean 28.194 ± 6.003 ug/ml) was significantly higher than the twice daily group (Group: 2) (mean 16.939 ± 5.19 ug/ml).About 96 % of all peak concentrations were ≥ 20 ug/ml in the once daily group compared to only 14 % in the twice daily group.The finding that no significant difference was found between the two regimens in renal function obviates the presence of more nephrotoxicity in the once daily regimen whose peak concentrations were significantly higher than the twice daily one, which favors its use for possible better effectiveness.