There is a need for better predictors for short survival in patients with brain metastases undergoing open surgery. The graded prognostic assessment (GPA) has recently been developed to predict survival in patients with brain metastases. We explored the prognostic capabilities of GPA in a consecutive neurosurgical population of brain metastases. Secondarily, we evaluated if GPA scores can provide information on safety of the operation and postoperative functional outcome. We retrospectively included all adult (≥ 18 years) patients undergoing open surgery for brain metastases from 2004 through 2009 (n = 141). The population was grouped into GPA 0-1 (n = 22, 16%), GPA 1.5-2.5 (n = 90, 64%), GPA 3 (n = 19, 14%), and GPA 3.5-4 (n = 10, 7%) according to the prognostic indices. Median survival times were 6.3 months (range 0.8-23.7) in GPA 0-1, 7.8 months in GPA 1.5-2.5 (range 0.2-75.0), 14.0 months in GPA 3 (range 0.0-77.4), and 18.4 months in GPA 3.5-4 (range 0.1-63.7). This represents a significant difference between groups (P = 0.010). There were no associations between GPA and 30-day mortality (P = 0.871), 3-month mortality (P = 0.750), complications (P = 0.330) or change in Karnofsky Performance status postoperatively (P = 0.558). GPA scores hold prognostic properties in patients operated for brain metastases. However, GPA did not predict short-term mortality, limiting the clinical usefulness in a neurosurgical population. The prognostic indices cannot be used alone to decide if surgery is warranted on an individual basis, or to evaluate risks and benefits of surgery.