Economic debate about the consequences of immigration in the United States has largely focused on how influxes of foreign-born labor with little educational attainment have affected similarly educated native-born workers. Fewer studies analyze the effect of immigration within the market for highly educated labor. We use O*NET data on job characteristics to assess whether native-born workers with graduate degrees respond to an increased presence of highly educated foreign-born workers by choosing new occupations with different skill content. We find that highly educated native and foreign-born workers are imperfect substitutes. Immigrants with graduate degrees specialize in occupations demanding quantitative and analytical skills, whereas their native-born counterparts specialize in occupations requiring interactive and communication skills. When the foreign-born proportion of highly educated employment within an occupation rises, native employees with graduate degrees choose new occupations with less analytical and more communicative content.