Background: Therefore ergonomic school equipment is required for students. School equipment that is not ergonomic can cause pain, discomfort, lack of concentration and cause posture problems. The problem of posture directly affects the backbone. Students who have bad habits in a sitting position for many years in a school environment have a great risk to experience structural disturbances of the spine.
Objective: The purpose of this research is to know the ergonomic analysis of chair and its relation to alignment vertebra in student class XII.
Research methode: The type of this research is survey approach with Cross Sectional Study. Sampling using purposive simple sampling technique. The number of samples meeting the inclusion criteria was 81 people. Intake of anthropometry measurement data of body dimension and dimension of chair using medline. Measurement of vertebral alignment using flexicurve. The obtained data were tested by chi square test through the crosstabulation
Result of research: The result of crossing between seat ergonomics and vertebral alignment shows a p value of 0.01. Since p < 0.05 then H0 is rejected, which means there is a relationship between ergonomic chair with alignment vertebra
Conclusion: There is a relationship between chair ergonomics and alignment vertebra in students class XII.
Keywords: antropometri, ergonomic, flexicurve, seats, vertebra