Publisher Summary This chapter addresses the advantages and weaknesses of continuous culture systems for their application to study a range of clinical and environmental biofilms. It is arguable whether any laboratory system can truly model the real world of biofilm formation and maturation, as this is a dynamic system subject to fluctuations of nutrient availability, growth rate, and shear rate, modified by predator–prey relationships and environmental parameters such as temperature, redox, and pH. Moreover, the physicochemistry of the substrata is altered by the complex nutrients of the local environment and the by-products of microbial metabolism adhering to the surfaces to be colonized. Nevertheless, laboratory studies form the basis of many of the observations on biofilm development, structure, microbial and chemical heterogeneity, and physiology. They offer the ability to dissect the effects of individual environmental and physicochemical parameters on biofilm structure and function, ideally in a reproducible fashion. Moreover, laboratory biofilm systems can be pushed to investigate the extreme of environmental parameters that are probably never encountered in situ. Many model systems have been developed to study biofilms, but each can be argued to suffer particular flaws such as lack of reproducibility, defined physicochemical environments or control of the growth rate, and inability to operate for long periods.