Adherence of Candida species to various host surfaces is an important prerequisite for colonization and pathogenesis. Researchers have problems in quantifying candidal adherence to plastic surfaces (used for fabrication of prostheses) due to coaggregation of adherent yeasts and to the laborious, time-consuming method of microscopic quantification. We describe here, a semi-automated image analysis system which is superior to conventional visual light microscopic techniques of quantifying yeasts attached to solid substrates such as acrylic. The results demonstrated a significant positive correlation between the number of cells quantified by traditional light microscopy and the corresponding area obtained by the semi-automated image analysis system (r = 0.83, P < 0.02). The new system is simple, less laborious and is particularly useful when the adherent attributes of a large battery of yeasts are characterized.