Narrow and broad range distributed ethoxylates of linear C-12-C-14 alcohols were synthesised using a calcium-based unconventional catalyst and NaOH, respectively. Their composition was determined by gas chromatography. Sulphates were synthesised in the traditional way by reaction of ethoxylates with sulphur trioxide in a film reactor and neutralised with sodium hydroxide. Products were characterized by the ethoxylate homologue distributions and acid value of the intermediate sulphuric acid derivatives. Viscosity build-up properties of the narrow and broad range distributed ethoxylates-based sodium alcohol ether sulphates were studied. Effects of ethoxylate homologue distribution were compared with those of average ethoxylation grade and sulphation degree. It was shown that the acid number of the obtained sulphates, ethoxylate homologue distribution, average polyaddition degree and sodium chloride content influenced remarkably the thickening ability of ethoxylates. Furthermore, it was found that the limited content of the longer ethoxylate chains in narrow range distributed alcohol ethoxylates is responsible for enhanced viscosity build-up properties of their sodium sulphate derivatives. The following empirical relationship was obtained: log eta = (2.99 +/- 1.25) + (3.78 +/- 0.86) x 10(-2) V - (1.48 +/- 0.15)N-av - (2.69 +/- 0.7) x 10(-2) A(N) + (0303 +/- 0.058) x C-surf + (0.832 +/- 0.041) x C-NaCl where eta is the viscosity in cP, V is the distribution coefficient, N-av is the average oxyethylation degree, A(N) is the acid number of alcohol ether sulphuric acid and C-surf and C-NaCl are concentrations (wt%) of the studied surfactants and sodium chloride, respectively.