The in vitro antimicrobial activity of meropenem, in comparison with nine other antimicrobial agents, against 12 different common pathogenic bacteria were evaluated to know the susceptibility of common bacteria to meropenem in Taiwan. Meropenem was active against most Gram-positive, Gram-negative, and anaerobic bacteria, including methicillin-sensitive Staphylococcus aureus, Streptococcus pyogenes, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, Pseudomonas aeruginosa, Burkholderia cepacia, Acinetobacter baumannii, Haemophilus influenzae, and Bacteroides fragilis. For many of them, meropenem was the most active one in comparison with other broad-spectrum cephalosporins, aztreonam, imipenem, and ciprofloxacin. It is concluded that meropenem is a very active agent against most common pathogenic bacteria. It is uncommon for these common bacteria, except MRSA and Stenotrophomonas maltophilia, to be resistant to meropenem in Taiwan, where a high prevalence of resistance to other antimicrobial agents was found in many of the common bacteria.