Purpose– To investigate the risk of seizure recurrence after a newly diagnosed unprovoked epileptic seizure in an adult population-based cohort. Material and methods– A total of 107 patients aged ≥17 years with a newly diagnosed unprovoked epileptic seizure (index seizure) were prospectively identified for the period 1985–87. Patients were followed until the date of death or to the end of 1996 with a median follow-up of 10.3 years for surviving cases. Overall cumulative recurrence rates and possible influencing variables were calculated. Results– At 750 days after the index seizure the recurrence was 58%, and after that no events occurred. Recurrence risk was significantly higher when index seizure was remote symptomatic or preceded by two or more seizures. No other study variable predicted seizure recurrence. Conclusion– Etiology and the occurrence of seizures before the index seizure after a newly diagnosed unprovoked epileptic seizure predict seizure recurrence. Thus, particular consideration should be given to these factors in the decision of whether or not to initiate antiepileptic treatment.