Bacterial adhesion to urinary catheter was evaluated by measuring the light emitted from a recombinant bioluminescent glycocalyx producer Escherichia coli strain. Generation of the bioluminescent strain was carried out by transforming the bacterial cells with pUCP18-GFP plasmid that contains a green fluorescence gene. Light emission measurement was closely correlated with the number of the adherent cells, giving a detectable signal from 1.2 X 10² cells. The efficiency of this assay was confirmed by testing the antiadherent effect of subinhibitory concentrations of ciprofloxacin with the aid of a model for in-vitro catheter colonization. There was no significant difference in the percentage reduction of adherent cells obtained by both light emission measurement and viable cell count techniques.