The assembling at Ungaran Hospital has one assembling staff to take Medical Record Document (MRD) in each rooms, assemble MRD and analyze completeness of MRD. Total estimation of time to complete the duty in one day are 15 hours, while working time each day around 7 hours. Needs of assembling staff at Ungaran Hospital must bereviewed to their workload.WISN Method is a method that advised by Health Department of Republic Indonesia for performing calculations of workers on demand. The purpose of this research to know needs of assembling staff with WISN method at Ungaran Hospital.The research is descriptive research with cross sectional approach. The data carried on assembling in Medical Record Instalation at Ungaran Hospital on May 13th 2016 until May 19th 2016. The Subject of the research are assembling staff, training unit and staffing unit in the Ungaran Hospital. The object of the research are activity of assembling staff that is taking MDR from inpatient rooms, writing on receipt book and MRD are assembled and analyzed. Data collection method is using primary data (interviews and observation) and secondary data. The analysis is the quantitative descriptive analysis.The calculation on assembling staff with the WISN method shows that the number of staff needs of assembling are 1,281 people with standard workload 2360,653 to the take MRD, 126408,788 to write on receipt book and 22890,366 to assemble and analyze MRD. Staff of assembling installation on Medical Record Department at Ungaran Hospital do not need to increase the number of worker if the workload is reduced.