The report describes a microcomputer system utilizing the Computerized Laboratory Notebook (CLN) concept developed for the purpose of automating the Battery of Leukocyte Tests (BLT). BLT was designed to evaluate blood specimens for toxic, immunotoxic, and genotoxic effects after in vivo exposure to putative mutagens. A system was developed with the advantages of low cost, limited spatial requirements, ease of use for personnel inexperienced with computers, and applicability to specific testing yet flexibility for experimentation. The system eliminates cumbersome record keeping and repetitive analysis inherent in genetic toxicology bioassays. Statistical analysis of the vast quantity of data produced by the BLT would not be feasible without a central database. The central database is maintained by an integrated package which is adapted to develop the CLN. The clonal assay of lymphocyte mutagenesis (CALM) section of the CLN is demonstrated. PC-Slaves expand the microcomputer to multiple workstations so that the computerized notebook can be used next to a hood while other work is done in an office and instrument room simultaneously. Communication with peripheral instruments is an indispensable part of many laboratory operations. The report presents a representative program, written to acquire and analyze CALM data, for communicating with both a liquid scintillation counter and an ELISA plate reader. In conclusion it discusses how the computer system could easily be adapted to the needs of other laboratories. (Copyright (c) 1989 Elsevier Science Publishers B.V.)