This paper reviews and analyzes the science, technology, engineering, and mathematics (STEM) labor market and workforce and the supply of high-skill temporary foreign workers¾referred to here as “guestworkers”—to address three central issues in the ongoing discussion about the need for high-skill guestworkers in the United States: First, is there a problem producing enough STEM-educated students at sufficient performance levels to supply the labor market? Second, how large is the flow of guestworkers into the STEM workforce and into the information technology (IT) workforce in particular and what are the characteristics of these workers? Third, what are the dynamics of the STEM labor market, and what are the employment and wage trends in the IT labor market? Analysis of these issues provides the basis for assessing the extent of demand for IT workers and the impact of guestworker flows on the STEM and IT workforces. Our examination of the IT labor market, guestworker flows, and the STEM education pipeline finds consistent and clear trends suggesting that the United States has more than a sufficient supply of workers available to work in STEM occupations. Our review of the data finds that guestworkers make up a large and increasing portion of the IT labor market. It could appear to casual observers that the striking increase in guestworkers might be a response to increased labor demand in the IT field. But employment and wage levels in IT jobs have been weak, trends which are not consistent with strong demand. The data also strongly suggest that there is a robust supply of domestic workers available for the IT industry.