People spend most of their time in indoor environments where they can be highly exposed to formaldehyde which is ubiquitous and abundant due to the presence of many emission sources. In French public places, its averaged concentrations can vary from 3 micro g m-3 to 60 micro g m-3. Because formaldehyde is of particular health concern (carcinogenic for human), it is important to be provided with suitable methods to measure its content in indoor air. This work presents the test of five different techniques in the INERIS simulation chamber and in indoor environments: passive and active sampling methods based on 2,4-dinitrophenylhydrazine (DNPH) reaction with formaldehyde, two online continuous monitoring systems based on fluorescence and UV measurements and a portable commercialised analyser based on electrochemical titration. The analytical and sampling problems associated with each measurement method have been identified and will be discussed. An overall agreement between each technique has been observed and continuous analyzers allowed for formaldehyde concentrations change monitoring and secondary formation of that pollutants observation.