Massive stars (M ≳ 8 Msun) play an important role in the evolution of the interstellar medium due to their high energy output, supernovae explosions, and enrichment of the surrounding medium by heavy elements. The formation of these stars can be studied through the HII regions formed due to the increased output of UV photons from them. Moreover, a multiwavelength study of the molecular clouds associated with these HII regions gives important clues about the evolutionary stages of star-formation. We have studied the southern HII region RCW 42 and its associated molecular cloud at radio, near, mid, far infrared and millimeter wavelengths to estimate its properties (column density, temperature, electron density, ionization fraction, bolometric luminosity) and study the evolutionary stages of various clumps present in the region. The HII region has been investigated by studying the ionized gas emission, emission from cold and warm dust and identifying its ionizing candidates. An extended green object EGO G274.0649-01.1460 has also been identified in the region. We have constructed column density and temperature maps and have identified five dust clumps from the former. We have also identified two mm emission cores towards the radio emission peak. All the five dust clumps are found to be in the active/evolved phase based on various star-formation tracers.