The spectrofluorimetric characteristics of chrysene, perylene, dibenz[a,c]anthracene and coronene were studied in aqueous medium and in the presence of cationic, anionic and non-ionic surfactants. The great enhancement of the fluorescence of these polycyclic aromatic hydrocarbons (PAHs) in hexadecyltrimethyl-ammonium bromide and synchronous fluorescence spectrometry were used for the establishment of two methods for the analysis of binary and ternary mixtures of these compounds. The former allows the simultaneous determination of dibenz[a,c]anthracene and coronene using Δλ= 89 nm, with detection limits of 0.20 and 0.22 ng ml^–1, respectively. In the latter, three different Δλ values are used for the simultaneous determination of chrysene, perylene and coronene, viz., 41, 3 and 140 nm, respectively. Limits of detection of 0.17 ng ml^–1 for chrysene, 0.13 ng ml^–1 for perylene and 0.14 ng ml^–1 for coronene were obtained. Good recoveries were obtained when both methods were applied to the analysis of binary and ternary mixtures of these PAHs added to sea-water.