In Tanzania maternal and perinatal mortalities and morbidities are problems of public health importance, and have been linked to the shortage of skilled staff. We quantified the available workforce and the required nursing staff for perinatal care in 16 health institutions in Dar es Salaam. WHO safe motherhood needs assessment instruments were used to assess the availability of human resources, WHO designed Workload Indicators for Staffing Need (WISN) and Tanzanian standard activities and components of the workload for labour ward nursing were used to calculate nurse staffing requirements and WISN ratios. There was a severe shortage of essential categories of health staff for perinatal care in all institutions. The ranges of WISN ratios for nursing staff working in the municipal hospitals' labour wards were; nurse officers 0.5 - 1, trained nurses/midwives 0.2 - 0.4 and nurse assistants 0.1. These findings reflect extremely huge perinatal care workload pressure and suggest the urgent need for more staff in order to achieve the global millennium development goals set for maternal and infant survival.