This analytical method is a validated measurement procedure for the determination of cobalt and its compounds in workplace air averaged over a sampling period after personal or stationary sampling. Sampling is performed by drawing a defined volume of air through a quartz fibre filter located in a FSP sampling head using a suitable flow-regulated pump. The flow rate is set to 10 l/min with a recommended air sample volume of 1200 l which corresponds to a sampling period of 2 h. The collected respirable dust fraction is treated with a mixture of sulphuric acid (65%) and hydrochloric acid (30%) and analysed using atomic absorption spectrometry with the graphite furnace technique (GFAAS). The quantitative determination is based on a calibration function obtains by means of a 10-point calibration. For the respirable dust of cobalt and its compound the limit of quantification (LOQ) is 0.058 μg/m3 based on an air sample volume of 1200 l. This method has been tested and recommended for the determination of cobalt and its compounds in the air at workplaces by the German Social Accident Insurance.