Measurements related to building acoustics include noise measurements, airborne and impact sound insulation, reverberation time, vibrations, loss factor, radiation efficiency and junction attenuation. Measurements can be made with various degrees of precision, and some measurement standards distinguish between three grades: survey, engineering and precision. The focus in this chapter is on field measurements in buildings at the engineering grade. It describes the principles of sound pressure level measurements in rooms when the sound source is equipment for building services or some outdoor noise source. The recommended choice of measurement positions for the sound pressure level in a room is very different for frequencies above or below the Schroeder limiting frequency Measurements of impact sound insulation should include the low frequencies down to the 50 Hz one-third octave band. Vibration measurements can be made both in vertical and horizontal directions.