Twelve horses underwent standing laparoscopic ovariectomy using electrocoagulation and fine dissection as the only means of achieving haemostasis of the severed ovarian pedicle. Four mares had bilateral ovariectomy performed as a treatment for aggressive behaviour thought to be associated with the oestrous cycle. Eight mares had unilateral ovariectomy performed for removal of a granulosa thecal cell tumour (gct). Electrocoagulation provided an effective means of haemostasis in both normal and pathological ovaries. Only one case (removal of a gct) had mild haemorrhage following electrocoagulation, necessitating the need for the application of endoscopic clips to achieve haemostasis. Six of the horses developed minor wound complications (none of them requiring any additional treatment). Long-term follow-up information showed complete resolution of abnormal behaviour in all eight horses with gcts, but in one of the four horses with normal ovaries the aggressive behaviour had not been completely resolved.