Data collection for transplantable solid tumors has been automated with electronic digital calipers and a balance which have been coupled through an RS-232 interface to a microcomputer. BASIC programs handle data entry, calculations and data storage. A "PROTOCOL" program accepts keyboard input of sample name, notebook number, submitter and dose along with necessary information on tumor system, and then initial animal weights for treatment groups are sent from balance to computer. Data is stored as an ASCII file on floppy disks, and protocol reports are printed. When the test is to be measured, a "MEASURE" program prompts the user for keyboard entry of toxic deaths in each group. Then the computer requests input of width and length of tumors for each animal. These tumor dimensions are sent to microcomputer by pressing a button on the calipers. When a group is completed, final animal weights are sent from balance to microcomputer. Then tumor weights and percent inhibition as compared to appropriate control groups are calculated, and the data is appended to the file for that test. A hard copy is generated as tumors are measured, and reports including percent inhibition can be printed immediately after a test is measured. The data as an ASCII file is transferred via modem to mainframe computer, where another program transfers the information to a database management program. These automated procedures for tumor measurement save time and lessen the chance for error by eliminating manual recording of solid tumor dimensions and subsequent reentry of this data for calculation.