Summary. A search was made at the frequency of the J = 1-0 line of HCN (88.6 GHz) using the CSIRO 4-m telescope at Epping (3.1 arcmin beam). Most of the observations were of molecular clouds associated with H ii regions. HCN emission was detected in at least 33 of 43 positions. A comparison is made with data for CS, HCO+ and CO; it is found that the HCN integrated intensities are significantly correlated with CS integrated intensities.