The aim of this study was to evaluate the variations in C7-T1 mobility in order to decide whether inverse C7-T1 function, defined as equal or less mobility in motion segment C7-T1 compared with T1-T2, could be used for prediction of neck-shoulder pain (NSP). One hundred and sixty-one female laundry workers participated in a prospective two-year follow-up study which included a self-report questionnaire and clinical examinations. The present study showed that the incidence of inverse C7-T1 function was 33% per year and subjects classified as having an inverse C7-T1 function three or more times during the follow-up period had an elevated risk of NSP (RR 3.1, CI 95% 1.1-6.9). According to the authors' interpretation, lack of synchronous mobility distribution between adjacent motion segments might be a provoking factor. Inverse C7-T1 function predicts NSP related to the cervico-thoracic articulations and yields a positive predictive value of 84%. Assessments must be repeated, however.