Scientific background: To date, there has been no standardised method to measure airborne fungi during the manufacture of sterile drugs. Airborne fungi can, however, be measured by multiple active or passive methods. The efficiency of these methods has been viewed sceptically and the correlation between active and passive methods of measurement is a much discussed and debated topic. Method: In this study active and passive methods of measuring airborne fungi are compared by impingement and sedimentation in an aerosol chamber. Different A. niger concentrations of spores will be used for the 30 measurements. The concentration of the starting suspension (KBE/ml) will be known at the start of every measurement. The AGI-30 from the companies Neubert-Glas and Ace Glass will be used as an impinger. Prior to each sample, the aerosol chamber will be filled with spore aerosol for an hour. The sedimentaion sample will be carried out over a one hour period and the impingement, 30 minutes. Malt-extract-agar- and dichlorane-glycerin-agar-plates will be used for the evaluation. Results: The correlation coefficient of > 0.9 clearly shows a high correlation in both methods of measurement. A ratio of 1:0.65 was found for the sedimentation and the impingement. Conclusion: The difference between the results is too small to justify a preference for the sedimentation method. Using the mathematical approximation of KBE/m3 it was only possible to calculate an ideal case of the tested air volume for the sedimentation. When choosing the most appropriate method, both the advantages and disadvantages should be thoroughly taken into consideration. To avoid the potential mistakes of a particular method, measurements should be taken using both methods.