The hygienic importance of barrier zoning in hospitals has been evaluated on the basis of the relevant international literature between 1970 and 1989. There have been only a very few pertinent publications and in none has there been any pointer which would support the hypothesis of barriers having an infection-preventing effect. Using four University Hospitals in Baden-Würtemberg as paradigms, a model was prepared for calculating what space and cost savings were possible, if a simpler system could be installed, instead of the one demanded under federal regulations and already planned for the four hospitals. It was found that it would save a realizable area of 319,5 m2 at a potential cost saving of DM 1,138,335. By dispensing with hygienically not justifiable building work at the planning stage of new hospitals considerable greater costs could be avoided.