50 patients underwent myelography on an outpatient basis; the incidence and severity of side effects were compared, in a prospective study, with 180 inpatient examinations over the same period. In addition, in the initial 200 myelograms (36 outpatients and 164 inpatient) iohexol and iopamidol were compared in a double blind trial. Headache was the most common side effect in both patient groups, recorded in 50% of outpatients and 25% of inpatients. Other side effects were of comparable incidence. 84% of outpatients undergoing myelography found it "acceptable", and did not consider a night in hospital necessary after the procedure. No difference in side effects was demonstrated between the two contrast media. This pilot study suggests that outpatient myelography is practical and safe, with considerable cost saving implications.