Dicathais orbita is a mollusc of the Muricidae family and is well known for the productionof the expensive dye Tyrian purple and its brominated precursors that have anticancer properties,in addition to choline esters with muscle-relaxing properties. However, the biosynthetic pathways thatproduce these secondary metabolites in D. orbita are not known. Illumina HiSeq 2000 transcriptomesequencing of hypobranchial glands, prostate glands, albumen glands, capsule glands, and mantleand foot tissues of D. orbita generated over 201 million high quality reads that were de novo assembledinto 219,437 contigs. Annotation with reference to the Nr, Swiss-Prot and Kyoto Encyclopediaof Genes and Genomes (KEGG) databases identified candidate-coding regions in 76,152 of thesecontigs, with transcripts for many enzymes in various metabolic pathways associated with secondarymetabolite biosynthesis represented. This study revealed that D. orbita expresses a number of genesassociated with indole, sulfur and histidine metabolism pathways that are relevant to Tyrian purpleprecursor biosynthesis, and many of which were not found in the fully annotated genomes of threeother molluscs in the KEGG database. However, there were no matches to known bromoperoxidaseenzymes within the D. orbita transcripts. These transcriptome data provide a significant molecularresource for gastropod research in general and Tyrian purple producing Muricidae in particular.