Working position is the posture formed naturally of bodywhich interact with facility workers and work habits in a clinical job. The effectiveness of a treatment is influenced by work posture. Ergonomic work posture produces good output, and vice versa. In addition, an ergonomic work position needs to be considered to prevent complaints from work-related diseases. Low back pain is a condition with discomfort or acute pain in the fifth and sacral lumbar region (L5-S1). The purpose of this study was to determine the relationship between demographic characteristic and work position with complaints of low back pain in dental therapists in Pati, Central Java Indonesia. Design research is an obeservasional studywithcross sectional approach. Population is all dental therapist, and sample is 37 of those who selected purposively. Respondent characteristic, complaint of low back pain was collected by questionnaire and determined of work position was by Rapid Entire Body Assesment(REBA). Relation of variables was analyzed by Chi Square test. Research study found no relationship of age, gender, and body mass index with complain of low back pain (p= 0.122 ;0.816; 0.761 and 0.208 respectively), in addition variable length of workingand working position were significantly has relation (p = 0.01and 0.02). Dental therapist need to concern with their working position to prevent of their complaint of LBP.