Observational studies of up to 12 months duration showed that glatiramer acetate (GA) treatment of relapsing-remitting multiple sclerosis may result in decreased fatigue and improves health-related quality of life (HRQoL), with no changes in disability or mood. We investigated whether in the second year of treatment these improvements are sustained, disability or mood yet improved, and 2-year changes may be predicted by changes in the first 6 or 12 months. The multi-center FOCUS-Extension study was a prospective extension of the 12-month, international, observational FOCUS study and included 67 patients (38 treatment-naïve, 29 pre-treated) of the Dutch FOCUS cohort. Fatigue, HRQoL, depression and disability were measured by the Fatigue Impact Scale (FIS), Leeds Multiple Sclerosis Quality of Life (LMSQoL) questionnaire, Beck Depression Inventory-Short Form and the Guy's Neurological Disability Scale. A 2-year period of GA treatment was associated with -0.52 and +0.66 standard deviation changes in mean FIS and LMSQoL scores compared to baseline, whereas disability and mood remained unchanged. For FIS and LMSQoL, the Pearson correlation coefficients between 6-month changes and 2-year scores were 0.47 and 0.50, and between 12-month changes and 2-year scores 0.65 and 0.62. After 2 years GA treatment, the improvements in fatigue and HRQoL observed at 1 year are sustained, whereas disability and mood remain unchanged compared to baseline. Moreover, the levels of fatigue and HRQoL at 2 years GA treatment are predicted by the improvements at 6 months.