We report here surveillance data on the bacterial resistance of clinical isolates from 11 Shanghai hospitals in 1999, for guidance in the clinical use of antibacterial agents. Of the 14,855 strains collected, 5130 (34.5%) were Gram-positive cocci and 9725 (65.5%) were Gram-negative bacilli. The most common organisms in descending order of frequency, were: Escherichia coli (16%), coagulase-negative staphylococci (CNS; 14.3%), Klebsiella spp. (12.3%), Staphylococcus aureus (11.5%), Pseudomonas aeruginosa (9.2%), Acinetobacter spp. (8.1%), and Enterococcus spp. (6.6%). Methicillin-resistant strains accounted for 64% and 77% of S. aureus and CNS, respectively. The methicillin-sensitive strains were susceptible to most agents tested, while most methicillin-resistant strains were resistant to these agents. No vancomycin-resistant staphylococci were identified. Vancomycin-resistant strains accounted for 3.6% of Enterococcus fecalis and 1.7% of E. fecium. E. coli strains resistant to piperacillin, gentamicin, and fluoroquinolones accounted for 50% or more of the strains, and the resistance rates of Klebsiella spp., Enterobacter spp., Citrobacter spp., and Acinetobacter spp. to third-generation cephalosporins had increased markedly compared with rates in recent years. Resistance rates of P. aeruginosa to ceftazidime and imipenem (27% and 20%, respectively) had also increased compared with rates in recent years. A national strategy on the limited and prudent use of antibiotics is urgently needed.