This document gives guidelines for the selection, use and maintenance of diffusive samplers used to analyse gaseous pollutants in indoor air including measurement strategy and planning. This document gives guidlines for the selection, use and maintenance of diffusive samplers used to measure indoor air quality and personal exposure. This document is applicable to indoor air quality assessment because crucial differences to ambient air measurement have to be taken into account concerning environmental parameters, measurement strategy, as well as the nature, number, source and abundance of indoor air pollutants.