A method has been developed for the simultaneous preconcentration of Cd(II), Co(II), Cu(II), Hg(II), Mn(II), Th(IV), U(VI), V(IV) and Zn(II) from 500–1000 ml of water samples by coprecipitation using a combination of 1-(2-thiazolylazo)-2-naphthol, ammonium pyrrolidinedithiocarbamate and ammonium salt of N-nitroso-phenylhydroxylamine. The elemental contents have been measured by neutron activation analysis using different schemes of irradiation, decay and counting periods. Quantitative recoveries of all the above elements have been achieved between pH 6.0 and 7.2. For most of the elements, the enrichment factors are of the order of 104. The precision, expressed in terms of relative standard deviation, and accuracy of measurements are within ±5–10%. The detection limits are in the ppb range. The method has been applied to sea and drinking water samples and biological materials.