In this article the linguistic features of three Italian Sign Language (Lingua Italiana dei Segni, or LIS) registers are analyzed focusing on iconic phenomena. Previous treatments of iconicity and motivation in spoken and signed language are discussed. Iconicity is defined as a regular mapping between expressive form and meaning that can be active in the citation form of signs and/or in discourse. Accordingly two major kinds of iconicity are devised in spoken and signed languages: (1) Frozen Iconicity, which affects citation forms and (2) Dynamic Iconicity, which is active in discourse. Three different kinds of LIS texts (poems, narrative, and conferences) are compared to assess to which degree Frozen Iconicity and different types of Dynamic Iconicity are present in each register. Articulatory features of signs in discourse such as two handedness, one handedness, coarticulation and simultaneous syntax are also examined. Analysis demonstrates differences in the presence of frozen and dynamic iconic features in the three registers: frozen iconic forms prevail in Poems and Dynamic Iconicity is particularly prevalent both in Poems and in Narratives. A comparable presence of coarticulation and simultaneous syntax affects the three different kinds of texts. Conclusions are drawn which point out that iconic features of signs are an important structural resource of SLs that can be enhanced in discourse according to different textual and situational contexts.