Between now and 1990, the number of classroom teachers needed in the United States will rise, from 2,380,000 in 1984 to a projected all-time high of 2,640,000 in 1990. Supplying qualified teachers to fill that record number of positions may be difficult, however. Among the reasons that many more teachers may be needed are increased enrollment; a new focus on mathematics, science, and technology; improved teacher-pupil ratios; the provision of new services for special pupils; and increased emphasis on training students for jobs. Among the reasons that teachers may be in short supply are the proliferation of policies to restrict entry into teaching and an erosion of the benefits and image of the profession. Currently, there is a severe shortage of mathematics and science teachers in many states. States have considered several policies to alleviate these shortages. One policy supports incentives, typically through undergraduate scholarship or loan programs, for college students to become science and mathematics teachers. Differential salary scales for mathematics and science teachers have been suggested, as have one-time bonuses. Other policies considered seek to link mathematics and science teaching more closely with industry. Several key policy considerations raised by teacher shortages are also discussed. (JMK)