Nosocomial infection rates in an old intensive care ward constructed in 1924 were compared with those in a new one constructed in 1986. The nosocomial infection rate in the old unit was 34.2% and that in the new unit 31.9%, with an average of 33%. The most frequent infections were: pneumonia, urinary tract infection, septicaemia and wound infection. After transfer of the intensive care unit (ICU) the incidence and profile of nosocomial infections remained the same. These findings suggest that the influence of architectural design has little impact on the incidence of nosocomial infections.