We report results on the pulsed laser deposition of ZnO obtained with the help of a new apparatus that includes in situ reflectron time-of-flightmass spectrometry, with a view to progress the understanding of the role of clusters in the laser deposition of nanostructured materials. Experiments were carried out using a Nd-YAG laser at its fundamental frequency and frequency tripled, with a fluence on target of similar to 7.7 J/cm(2), in vacuum (10 (4) Pa) or oxygen (1 Pa) atmospheres. The results show that under certain conditions there is preferential clusterisation of the material into certain mass numbers and finally that there exists a correlation between cluster presence in the plume and the deposition of nanostructures. (C) 2008 Elsevier B. V. All rights reserved.