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Nonsense-mediated RNA decay (NMD) is known as a mechanism for degradation of dysfunctional transcripts that contain premature termination codons (PTC). In many organisms the PTCs are recognized because of the increased distance from the poly A tail. Recently NMD has been shown to limit RNA virus replication in plant and mammalian systems. Dicistroviruses are (+) RNA viruses of invertebrates. Their genomes contain two ORFs controlled by specific IRESes. Stop codon of the first ORF is located >3 kb from the poly A sequence making viral RNA a potential target of NMD. Here we show that some viral sequences following the first exon’s stop codon and encoding the itergenic IRESes are capable to inhibit NMD. In this study we analyzed IRESes from Cricket paralysis virus (CrPV), Drosophila C virus (DCV) and Black queen cell virus (BQCV). We have generated transgenic flies expressing the IRES-containing bicistronic transgenes with long 3’UTRs. The comparative analysis performed by Northern blot and qPCR in NMD-competent and NMD-deficient flies revealed that DCV and CrPV intergenic IRESes, but not the BQCV-derived one, are able to protect the full length transcripts from NMD-mediated degradation. While IRES-lacking control and BQCV IRES-containing constructs displayed a strong increase in NMD-null background when compared to the wild type, the upregulation of DCV and CrPV-containing transcripts was minor or absent. Our results suggest IRES-containing transcripts are able to avoid recognition by NMD machinery, rather inducing a global NMD inhibition. To our knowledge these are the first RNA sequences acting as NMD inhibitors found in cytoplasmic viruses. While the direct effect of NMD on viral replication was not detected, the ability of dicistrovirus IRESes to protect their RNAs suggests this mechanism is antiviral in insects. This finding provides an unexpected example of functional multiplicity of RNA structures in viruses with limited genome sizes.