We develop state-level proxies for informal employment using differences between measures of self-reported employment and officially sanctioned employment. In construction and landscaping, industries associated with under-the-table labor, we develop proxies for informal work based on productivity per officially sanctioned worker. We relate each set of proxies for informal employment to changes in immigrant population and composition. We find some evidence that immigration is associated with informal employment generally and in the construction industry when prevailing wages are low. States with high concentrations of low-skilled male immigrants have higher levels of informal employment in the landscaping industry.