The authors of this retrospective study have developed a preoperative trigeminal neuralgia (TN) grading system for the preoperative prediction of long-term pain relief after microvascular decompression (MVD). Patients who had become refractory to or developed toxicity to carbamazepine or oxycarbamazepine and had undergone MVD were included in the study. Based on preoperative clinical and imaging results, the TN grading system was devised to predict outcomes after MVD. The variables considered for the grading were the type of TN symptoms, response to anti-seizure medication, and absence or degree of neurovascular compression (NVC). The clinical outcome immediately after MVD and again at last clinic visit, phone or email was assessed using a commonly used TN outcome scale. The authors’ TN grading system showed good discriminatory prediction ability in patients with classical TN, positive response to carbamazepine and/or oxcarbazepine preoperatively, and presence and nature of neurovascular compression demonstrated on MRI. The authors conclude that an overall net reduction of 20 per 100 cases was likely to be unsuccessful for patients evaluated with this grading system. As the study includes data of patients operated on by a single surgeon, it eliminates surgeon-related confounding factor and adds a level of consistency. However, demographics like age were not included amongst the variables for the TN grading system and that could contribute to pain outcomes. It will be interesting to observe use of this grading system by other neurosurgeons and their ability to predict pain outcomes after MVD for TN.