Effective empiric treatment of pneumonia requires antibiotic coverage against gram-negative and gram-positive pathogens, including drug-resistant isolates. This study evaluated the efficacy of cefepime treatment in 20 patients with community-acquired pneumonia (CAP) and 21 patients with hospital-acquired pneumonia (HAP), and ceftazidime treatment in 20 patients with HAP. The mean age of patients was over 70 years. More than half of the patients had multiple lobe involvement. There was no significant difference in the severity of illness according to the acute physiology, age, chronic health evaluation (APACHE) III score between the HAP-cefepime and HAP-ceftazidime group. The most common bacteria isolated from sputum of patients with CAP were Streptococcus pneumoniae (n = 7), Klebsiella pneumoniae (n = 4), and Pseudomonas aeruginosa (n = 2). In patients with HAP, P. aeruginosa (n = 13), Acinetobacter baumannii (n = 11), Serratia marcescens (n = 6), K. pneumoniae (n = 5), Stenotrophomonas maltophilia (n = 5), Enterobacter cloacae (n = 3), Citrobacter spp. (n = 2), and Escherichia coli (n = 2) were isolated. The cure rates were 95%, 76%, and 60% in the CAP-cefepime group, the HAP-cefepime group, and the HAP-ceftazidime group, respectively. The increased rates of antimicrobial resistance commonly found among isolates causing CAP and HAP indicate that extended-spectrum antimicrobial agents, such as cefepime, would be more appropriate therapeutic agents.