A series of 85 patients having what are defined as small, deep intracranial arteriovenous malformations (AVMs) is analysed in terms of presentation, investigation, treatment and outcome. This group of patients is taken from a consecutive series of 306 patients with AVM treated over a 20 year period. The anatomical distribution was as follows: cerebral hemisphere 54 patients, basal ganglia and thalamus 6 patients, brain stem and cerebellum 19 patients and deep dural 6 patients. Haemorrhage, both subarachnoid and intraparenchymal, was the predominant mode of presentation (71 of 85 cases). Other presentations were with epilepsy (5 cases), headache only (4 cases), progressive focal deficit (1 case) and mixed (4 cases). The vast majority of patients (71 of 85, 83.5%) were treated surgically: 67 by surgery only, 3 by surgery following partial embolisation and one with focussed irradiation after subtotal excision. The overall outcome in this group at 1 month was 27 (38.0%) improved (largely due to haematoma removal), 42 (59.2%) unchanged and 2 (2.8%) worse. One of the unchanged group died during the second month with pulmonary complications following prolonged impairment of consciousness. The two patients worse at 1 month (Gd I -> Gd II) returned to Gd I within 3 months. There were 3 patients treated non-surgically (2 by focussed irradiation and 1 by embolisation) while 11 patients were not treated because they declined treatment (3 cases), they died before treatment could be carried out (3 cases), or treatment was deemed inadvisable (5 cases). The results of surgical treatment in small deep AVMs are compared with those of other treatment modalities, in particular focussed irradiation. It is argued on the basis of these figures that surgery remains the best treatment for these lesions.