A system for machine assisted karyotyping and chromosome analysis has been developed. The system uses a drum- or TV-scanner as input device, runs provisionally in 32 K memory, and also allows human interaction on several stages. The accuracy with which banded chromosomes are karyotyped depends strongly on the type of classifier and varies from 40 up to 80%. The accuracy of the human assisted classifier (98%) comes close to that of a skilled technician (99.5%) using manual chromosomal analysis. Due to technical and memory limitations, the time necessary for the karyotyping of one cell is too long and depends on the interaction time; however karyotyping within 5 min, including human interaction, will be possible in the near future.