It is a traditional classical instrument used in Tamil Nadu, Andhra Pradesh, Karnataka and Kerala. This instrument is "among the world's loudest non-brass acoustic instruments". It is a wind instrument similar to the North Indian shehnai but much longer, with a hardwood body and a large flaring bell made of wood or metal. In Tamil culture, the nadaswaram is considered to be very auspicious, and it is a key musical instrument played in almost all Hindu weddings and temples of the South Indian tradition.

It is part of the family of instruments known as mangala vadya. The instrument is usually played in pairs, and accompanied by a pair of drums called thavil. It can also be accompanied with a drone from a similar oboe called the ottu.

The nadaswaram has seven finger-holes, and five additional holes drilled at the bottom which can be stopped with wax to modify the tone. The nadaswaram has a range of two and a half octaves, similar to the Indian bansuri flute, which also has a similar fingering.

Unlike the flute where semi and quarter tones are produced by the partial opening and closing of the finger holes, in the nadaswaram they are produced by adjusting the pressure and strength of the air-flow into the pipe. Due to its intense volume and strength it is largely an outdoor instrument and much more suited for open spaces than for indoor concerts.