Blood flow patterns have been studied in 28 patients with soft tissue sarcoma (29 tumours) using 99mTc-labelled hexamethyl propyleneamineoxime with planar views of the tumour-bearing region. Tumour:background ratios ranged from 1.13 to 6.60 (mean 2.74) and maximum:minimum tumour ratios (between peripheries and centres of tumours) ranged from 1.34 to 32.0 (mean 4.70). In eight of 29 tumours (seven of which were involving the trunk) the tumour could not be identified. This study demonstrates that the blood supply to soft tissue sarcomas is generally greater than that to adjacent normal tissues and that tumour centres are relatively underperfused compared with the tumour periphery. In this heterogeneous series there was no clear-cut relationship between blood flow and histological grade or type.