The marble crab Pachygrapsus marmoratus inhabits the rocky shores of the Mediterranean Sea, Black Sea and East Atlantic Ocean. As other intertidal species, it is considered a model species to study the effects of environmental stressors on natural populations. In this study, we performed Illumina next-generation sequencing on eleven P. marmoratus specimens with the aims to (i) reconstruct their whole transcriptome, (ii) perform a functional annotation of the assembled transcriptome and (iii) develop gene-based markers for future genetic and genomic studies on this as well as other brachyuran species. We obtained a transcriptome assembly constituted by 56.308 unigenes and covering about 60.3 Mbp. We detected 43.915 Simple Sequence Repeats (SSRs) and 192.631 high-quality Single Nucleotide Polymorphisms (SNPs). Due to the scarcity of genomic resources in decapods, and crabs in particular, our results constitute a valuable resource for future studies on brachyuran crabs. The present data also represent a sound resource to investigate biological responses to pollution in intertidal and marine populations. - Keywords: Crab, Crustacean, de novo transcriptome assembly, Decapoda, Marine pollution