AIMS--This study was designed to compare suture needle drainage (SND) with argon laser drainage (ALD) of subretinal fluid. METHODS--A prospective, randomised, controlled, clinical trial was carried out on 93 patients undergoing external drainage of subretinal fluid during scleral buckling surgery for rhegmatogenous retinal detachment. The incidence of successful drainage, incidence of subretinal haemorrhage, incidence of retinal incarceration, and incidence of retinal perforation were determined. RESULTS--The success rate was 97.9% in the ALD group and 84.8% in the SND group (difference-13.1%, 95% CI-26.4% to 2.0%). The incidence of clinically significant subretinal haemorrhage was 4.3% in the ALD group compared with 28.3% in the SND group (difference 24.0%, 95% CI 7.6% to 40.4%). The incidence of incarceration was comparable in each group. There were no cases of retinal perforation. CONCLUSIONS--The use of ALD was associated with a higher rate of successful SRF drainage, and a lower incidence of clinically significant subretinal haemorrhage than SND. ALD is preferred when an endolaser is available.