The levels of antibacterial amongst 991 strains responsible for significant bacteriuria, isolated in central Scotland at the end of 1990, have been determined by breakpoint sensitivity testing. Overall resistance to the commonly used antibacterials for UTI, trimethoprim and ampicillin was 23% and 36%, revealing that resistance to these agents in central Scotland had not significantly changed over the last ten years. High levels of ampicillin resistance have led to the widespread use of amoxicillin in combination with the beta-lactamase inhibitor clavulanic acid. The effectiveness of this approach was demonstrated by the fact that resistance among these urinary isolates to amoxicillin/clavulanic acid was only 6%. More detailed examination of Escherichia coli isolates, which were ampicillin-resistant, revealed that the addition of clavulanic acid restored sensitivity in 97.5% of the strains.