In pediatric emergency department (PED), bloodstream and lower airway infections are the most common infections. Because of multiple factors, PEDs are known sources of antimicrobial-resistant organisms. Bacterial resistance to antibiotics is growing up day by day in both community and hospital setting, increasing mortality and morbidity. The purpose of the present study was to determine the causative organisms, antimicrobial resistance patterns and outcome of different types of infections in patients admitted in pediatric emergency department of Cairo University Specialized Pediatric Hospital (CUSPH) aiming to be able to design antibiotic policy for pediatric emergency department. Different clinical samples were collected properly from 388 patients suffering from commonest infections in ER unit. Different specimens were cultured and the isolates were identified by the routine biochemical reactions. Antimicrobial susceptibility (AST) of all isolates were determined by the standard Kirby Bauer disc diffusion method. It was found that the most common organism isolated from patients with pneumonia was pseudomonas (27.7%), while CONS was the most prevalent among patients with sepsis (42.9%) and E.coli among patients with UTI (7/11) 63.6%. Gram negative organisms isolated from blood showed highest sensitivity to: ciprofloxacin (CIP) 67%, aztreonam (ATM) 53.6% and gentamycin (GN) 41.3%, while Gram positive organisms, showed highest sensitivity to: vancomycin (VA) 100%, teicoplanin (TEC) 86.5% and clindamycin (DA) 42.5%. Gram negative organisms isolated from BAL showed highest sensitivity to: ciprofloxacin (CIP) 43.4%, imipenem (IPM) 42.3% and meropenem (MEM) 37% , while Gram positive organisms showed 100% sensitivity to vancomycin (VA), teicoplanin (TEC), clindamycin (DA) and erythromycin (E) and 66% to doxycycline (DO). Gram negative organisms isolated from urine culture samples showed highest sensitivity to: ciprofloxacin (CIP) 83.3%, meropenem(MEM) 44.3% and amikacin (AK) 25%, while Gram positive organisms showed 100% sensitivity to vancomycin(VA), 100% to gentamycin (GN), 0% to doxycycline (DO). Antibiotic sensitivity pattern in cases of pneumonia showed that the most sensitive antibiotics include ciprofloxacin (CIP), imipenem (IPM) and meropenem (MEM), in cases of sepsis include vancomycin (VA), teicoplanin (TEC), and clindamycin (DA) and in cases of UTI include ciprofloxacin (CIP), ceftazidime (CAZ) and amikacin (AK). Antibiotic sensitivity pattern in cases of community acquired infections showed that the most sensitive antibiotics in Gram negative organisms were as follows: ciprofloxacin (CIP), imipenem (IPM), meropenem (MEM) and amikacin (AK), while the most sensitive antibiotics in Gram positive organisms were vancomycin (VA), teicoplanin (TEC) and clindamycin (DA). Antibiotic sensitivity pattern in cases of hospital acquired infections showed that the most sensitive antibiotics in Gram negative organisms were as follows: ciprofloxacin (CIP), imipenem (IPM) and meropenem (MEM), while the most sensitive antibiotics in Gram positive organisms were vancomycin (VA), teicoplanin (TEC) and clindamycin (DA). This antibiotic policy is updated periodically according to microbiology laboratory reports according to the most prevalent organism and most sensitive antibiotics in each sample.