We examined 69 soft tissue tumours for DNA content. Altogether 42 aspiration cytology and 27 imprint Feulgen-stained smears, each verified by histology, were analysed and the results evaluated with Böckings's algorithm. Except one false negative case (extramedullary ependymoma) 43 malignant and 25 benign soft tissue tumours could clearly be separated on the basis of their DNA content. The sensitivity of the positive cases (suspicious and malignant) came up to 97.7% with a false negative ratio of 2.2% while the sensitivity of the negative cases (benign) proved to be 75% with a 0% false positivity ratio. Cytometry is a useful aid in aspiration cytology diagnostics of soft tissue tumours particularly when their benign or malignant character is to be determined because the primary surgical therapy and consequently the further fate of patient, too, depend on the precise cytological diagnosis.