The objective of this follow-up study was to determine the long-term outcome in patients treated with antibiotics for strictly classified cases of neuroborreliosis. A one-year prospective population-based survey of Lyme borreliosis was conducted in southern Sweden, 1992-1993. Totally 349 identified cases with suspected neuroborreliosis were registered. Of those, 130 were classified as definitively neuroborreliosis and followed up five years later. Medical records were reviewed and all participants filled in a questionnaire. Totally, 114/130 (88%) completed the follow-up of whom 111/114 (97%) had fulfilled the initial antibiotic treatment. Of these, 86/114 (75%) had recovered completely and 70 (61%) recovered within six months. However 28/114 (25%) suffered from remaining neurological symptoms such as facial palsy, concentration disorder, paresthesia and/or neuropathy. The longer the duration from the neurological symptoms onset to antibiotic treatment the higher was the rate of sequelae. Of those who were treated within 30 days 5/32 (16%) and of those who were treated after 30 days 16/41 (39%) respectively, reported sequelae. Women suffered significantly more from sequelae compared to men, this difference was not seen among the children. No significant differences between the different antibiotic treatments given and experience of sequelae were seen. To conclude, we found that 25% (95% CI 17% to 33%) of the patients suffered from remaining neurological symptoms five years post treatment. However, the clinical outcome of treated neuroborreliosis is favourable as only 14/114 (12%) of the patients had sequelae that influenced their daily activity post treatment and early diagnosis and treatment seems to be of great importance to possibly avoid also these cases.