Conventional treatment of idiopathic chylothorax (IC) involves thoracic duct (TD) ligation (with/without lymphagiography) combined with subphrenic pericardiectomy. Nine dogs and four cats with IC, which received intrathoracic omentalisation with TD en bloc ligation (not preceded by lymphangiography) and subphrenic pericardiectomy, were evaluated retrospectively. Seven of nine dogs and 3/4 cats were still alive and disease-free at the time of reporting (range 10–53 and 19–31 months, respectively). Clinical signs of IC did not decrease after the first surgery in one cat and one dog; in another dog clinical signs recurred after 5 months. Overall efficacy rate of this one-stage combined procedure was 77% (6 months), 73% (12 months), and 57% (24 months). Where a second surgery was performed in case of failure, the success rate in dogs was 89% (6 months) and 80% (24 months). Addition of pleural omentalisation to TD en bloc ligation and subphrenic pericardiectomy does not seem to improve results when compared with published data and at present does not seem advisable as a first choice.