Beginning in 1976, DCRT developed and installed 11 Laboratory Data Acquisition and Control System (LDACS) computer systems throughout Building 2. Based on DEC LSI-11 microcomputers, the LDACS computers were connected to laboratory instruments for control and data collection. Collected data were transferred to a central computer over low-speed serial lines for further processing. We have replaced the three LDACS computers still in routine use, for which commercial equivalents systems are not available, with PC computers. The new systems will perform the same functions as the LDACS but will be connected to the building LAN. The new computers will be equipped with the appropriate interface components to control the laboratory instruments. Currently available desktop computers are considerably less expensive ($5K-$10K), offer more performance, and are potentially less difficult to program than the original LDACS. The software is modular: small programs to perform minimal tasks (i.e., temperature measurement) invoked from a general user interface program. The user interface has a high degree of compatibility with the existing LDACS system and user screens are easily modified. It is anticipated that this system will be general enough for use in other research labs at NIH.