In this chapter we discuss the different instrumentation components as used for gathering seismic data. It discusses briefly these components as typically used in seismic exploration: the seismic sources (air gun at sea and dynamite and the so-called Vibroseis source on land), the seismic sensors (hydrophones at sea and geophones on land) and the seismic acquisition system. The effects of these components can usually be directly observed in the seismic records, and the aim of this chapter is that the reader should become aware of the contribution of these components.