Cells monitor the quality of their mRNAs and degrade any transcripts that are poorly or incompletely translated. In the nematode Caenorhabditis elegans, degradation by the mRNA surveillance pathway depends on seven smg genes. Three of these genes also have a role in a second mRNA degradation pathway called RNA interference (RNAi), which is triggered by double-stranded RNA (dsRNA). Here I describe what is known about the smg genes and their potential functions in these two mRNA degradation pathways.