Background: The aim of this study was to assess the validity and reliability of the Patient Enablement Instrument (PEI) in Finnish health care centre patients. A pilot study was conducted to assess the content validity of the PEI. A questionnaire study in three health care centres in Western Finland was performed in order to assess acceptability, construct validity, internal consistency, and measurement error of the instrument. A telephone interview 2 weeks after the appointment was performed to evaluate reproducibility. Results: The pilot study with 17 participants indicated good content validity of the PEI. In the questionnaire study, altogether 483 with a completed PEI score were included in the analyses. Factor analysis and item-scale correlations suggested high structural validity. The internal consistency of the instrument was high (Cronbach’s α = 0.93). The PEI score diminished strongly over the two-week period. Conclusions: The PEI has good content validity and acceptability, good construct validity, high internal consistency but low reproducibility. Thus, the PEI seems to be an applicable tool to measure patient enablement in Finnish primary health care.