OBJECTIVES: To examine the feasibility of using laser energy during nerve-sparing robotically assisted radical prostatectomy (RARP), as the energy sources currently used for haemostasis in RARP adversely affect cavernous nerve function, while clips require application by a skilled assistant, but laser energy potentially allows precise dissection with minimal collateral tissue injury. MATERIALS AND METHODS: We used laser-based RARP in 10 dogs, using the da Vinci S system (Intuitive Surgical, Sunnyvale, CA, USA) and a prototype robotic laser instrument. The potassium-titanyl-phosphate laser was used for dissection at 2-6 W, with intermittent use of the neodymium-doped yttrium-aluminium-garnet laser at 5 W for coagulating larger vessels. The peak intracavernosal pressure response to nerve stimulation was recorded as a percentage of mean arterial pressure (ICP%MAP) before and after RARP. Five dogs were killed immediately after RARP and five were maintained alive for 72 h; the haemoglobin and haematocrit levels were measured before and after RARP in the latter five dogs. RESULTS: All 10 procedures were performed solely using laser energy and no additional haemostatic manoeuvres. The median prostate excision time was 65 min. The ICP%MAP before and after RARP (median 98.5% and 77.0%, P = 0.12) were not significantly different; similarly, the respective haemoglobin (median 14.4 vs 12.6 g/dL, P = 0.06) and haematocrit levels (45.1% vs 40.2%, P = 0.06) were not significantly different. Two dogs had catheter-related complications and one had an anastomotic leak. There were no laser-related complications or postoperative haemorrhage. CONCLUSIONS: Laser RARP is feasible in dogs and further assessment is warranted. © 2008 The Authors.