This paper presents a computer study of electrical and morphological properties of composite and nanocomposite films by help of self-made analytical software tools. Main attention is devoted to a relationship between the electrical properties and the morphology of the films. Methods of mathematical morphology are used to obtain structural parameters. A Monte Carlo method and the theory of percolation are used for the study of electrical properties. Conductivity is supposed to be either ohmic or by tunnel effect, or both in parallel. Current paths inside the composite structure form so-called fuzzy clusters below and especially close to the percolation threshold. Their study produces valuable additional information. The results of the morphological and transport analyses are compared and discussed. From them, information is searched about the processes. (C) 2011 Elsevier B.V. All rights reserved.